WO2018193109A1

WO2018193109A1 - Mems converter for interaction with a volume flow rate of a fluid, and method for producing same

Info

Publication number: WO2018193109A1
Application number: PCT/EP2018/060222
Authority: WO
Inventors: Harald Schenk; Holger Conrad
Original assignee: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Priority date: 2017-04-21
Filing date: 2018-04-20
Publication date: 2018-10-25
Also published as: DE102017206766A1; KR20190141721A; EP3612493A1; US11554950B2; TWI717597B; JP2020521347A; CN110785374A; US20200087138A1; TW201902812A

Abstract

The invention relates to a MEMS converter for interaction with a volume flow rate of a fluid, the MEMS converter comprising a substrate which has a layer stack with a plurality of layers forming a plurality of substrate planes, and which has a cavity in the layer stack. The MEMS converter comprises an electromechanical converter which is connected to the substrate in the cavity and has an element which can be deformed in at least one plane of movement of the plurality of substrate planes, wherein a deformation of the deformable element in the plane of movement and the volume flow rate of the fluid are causally related. The MEMS converter comprises an electronic circuit which is located in a layer of the layer stack, wherein the electronic circuit is connected to the electromechanical converter and is designed to provide a conversion between a deformation of the deformable element and an electric signal.

Description

MEMS converter for interacting with a volumetric flow of a fluid and method for producing the same description

The present invention relates to a MEMS converter for interacting with a volumetric flow of a fluid, such as a MEMS loudspeaker, a MEMS microphone or a MEMS pump, and in particular MEMS transducers with an integrated electronic circuit. The present invention further relates to a device having such a MEMS converter and to a method for manufacturing a MEMS converter. Further, the present invention relates to MEMS-CMOS (complementary metal oxide semiconductor) loudspeaker systems on a chip.

One focus of MEMS technology (MEMS = microelectromechanical system), in addition to its miniaturizability, is the potential for cost-effective manufacturability of the component in medium and high volumes. Electroacoustic MEMS loudspeakers are currently being insignificantly commercialized. With a few exceptions, MEMS loudspeakers consist of a diaphragm, which is deflected quasi-statically or resonantly by a selected physical action principle. The deflection depends linearly or non-linearly on the applied electrical signal (current or voltage). The signal has a temporal variation, which is transmitted in a temporal variation of the diaphragm deflection. The reciprocating motion of the membrane is transmitted in the form of sound in the surrounding fluid, for the sake of simplifying but not limiting air can be assumed in the following. In some cases, the actuation of the membrane takes place in one direction only. The restoring force is then provided by the mechanical spring effect with diaphragm deflection. In other cases, the actuation takes place in both directions, so that the membrane can have a very low rigidity.

For the actuation of the membrane, the use of electrostatic, piezoelectric, electromagnetic, electrodynamic and magnetostrictive action principles is described. An overview of MEMS transducers based on these principles can be found, for example, in [1]. Electrostatically operated converters are based on the force which results between two planar electrodes covered with different electrical potential. In the simplest case, the arrangement corresponds to a plate capacitor, wherein one of the two plates is movably suspended. In practice, the movable electrode is designed as a membrane to avoid an acoustic short circuit. When a voltage is applied, the membrane warps in the direction of the counterelectrode. In a specific embodiment, the membrane is operated in the so-called touch-mode. In this case, the membrane touches the lower electrode to which a thin insulator layer is applied to avoid a short circuit, as described, for example, in [2]. The bearing surface is determined by the size of the applied electrical voltage and thus varies in time according to the time course of this voltage. The oscillation thus generated serves to generate sound. In principle, in the classical electrostatic structure, the membrane can be attracted only in the direction of the electrode. The restoring force can be determined at least in part by the rigidity of the membrane and must be sufficiently high in order to be able to transmit the higher frequencies in the area of auditory sound.

On the other hand, with a given electrical voltage, the deflection of the membrane can decrease with increasing rigidity. To avoid this problem, an approach with a very soft membrane was developed, which can then be driven by an upper and lower electrode and thus deflected in both directions, as described in [3]. This loudspeaker uses a total of two such diaphragms suspended inside a cavity which, like a micropump, has an inlet and an outlet and is otherwise closed.

Piezoelectric powered converters use the inverse piezoelectric effect. An applied electrical voltage leads to a mechanical stress in a solid. In MEMS technology typically materials such as PZT (lead zirconate titanate), AIN (aluminum nitride) or ZnO (zinc oxide) are used. These materials are usually applied as a functional layer on a membrane and structured so that the membrane depending on the electrical voltage applied to the functional layer, can be deflected or excited to vibrate. A disadvantage of piezoelectric functional layers is the fact that the operation can not be done without hysteresis. In addition, the integration of the ceramic functional layers is complex and due to the lack of CMOS compatibility (CMOS = comple- mentary metal oxide semiconductor, complementary metal oxide semiconductor) in PZT and ZnO only under strict contamination control or equal in a separate clean room area possible. Electromagnetically operated transducers are based on the force effect that a soft magnetic material undergoes in a spatially variable magnetic field (gradient). For the implementation of the principle, a permanent magnet and a coil is required in addition to the soft magnetic material, by means of which the local gradient of the magnetic field via current flow can be controlled in time. The soft magnetic material is integrated, for example, in the membrane. All other components are provided in the assembly, as described for example in [4]. The structure is voluminous, complex and does not seem to make sense to scale for high volumes.

Electrodynamically operated converters make use of the Lorentz force. This method, which is very widespread in macroscopic loudspeakers, has also been used in some MEMS loudspeakers. The magnetic field is generated by a permanent magnet. A current-carrying coil is placed in the magnetic field. Usually, the coil is integrated into the membrane by deposition and structuring of a metal layer and the permanent magnet is added as an external component in the assembly. The complexity and limitations of integrating all components into MEMS technology are a similar drawback as with electromagnetically driven transducers.

Magnetostrictively operated converters are based on a contraction or expansion of a functional layer when the magnetic field is applied. For example. For example, vanadium permadur is positively magnetostrictive, that is, exhibits expansion when the magnetic field is applied. This contraction can be used with a suitable structure for generating a membrane vibration. In [1], vanadium permendur (Fe ₄₉ Co ₄₉ V ₂ ) was used as the magnetostrictive functional layer, which was deposited on Si0 ₂ (silicon dioxide) via a chromium adhesive layer. The external magnetic field is provided by a microflake coil realized by electrodeposited copper. Concerning complexity and restrictions in the integration similar disadvantages are to be mentioned, as with the two aforementioned active principles. The classic and most widely used variants described above, which have as a common feature the use of a membrane which leads to a Oscillation can be excited, is subsequently supplemented by certain modifications, which were examined due to special disadvantages of the classical membrane principle. Flexible membranes can also have higher modes in the field of audible sound and thus lead to parasitic vibrations, which lowers the acoustic quality (harmonic distortion), cf. [1]. To avoid or reduce this effect, therefore, plates are used which have a significantly higher rigidity. Such a plate is connected via a very soft suspension, which should also avoid the acoustic short circuit, connected to the chip, see [5].

Another variation is a segmented membrane used in the magnetostrictive transducers described above. This corresponds to a special topographical solution to the problem that the functional layer contracts or expands in two directions. Specifically, the structure consists of several deflectable bending beam. According to [1], the arrangement for distances of the bars less than or equal to 3 pm can be regarded as acoustically closed. By appropriate dimensioning of the individual beams with respect to a resonance frequency and the distances between the beams, a comparatively high acoustic bandwidth can be achieved and the course of the sound level can be adjusted or optimized as a function of the vibration frequency.

Neumann et al. pursue in [6] the approach to use instead of a single, large membrane a variety of small sub-membranes. Each partial membrane has such a high resonance frequency that a quasi-static deflection can take place in the area of the audiophile sound. This allows in particular a digital operation of the speaker.

In summary, it can be concluded that known electrostatically operated membrane loudspeakers have relatively low deflections with regard to integration if moderate drive voltages are assumed. As a reference, for example, the electrostatic membrane speaker of Kim et al. serve according to [3]. Each of the two membranes has an area of 2 x 2 mm ² . At a distance of 7.5 pm each, the upper and lower electrodes are attached. Depending on the geometry of the membrane and the increase in membrane stiffness with increasing deflection, the deflection due to the so-called pull-in effect is limited to typically 1/3 to 1/2 of the electrode spacing. If the higher value of 1/2 is assumed, the result is for the deflection 7.5 pm / 2, once in one direction and once in the other direction. The displaced volume can be estimated by assuming that it corresponds to the volume of a deflected rigid plate with a deflection of half the maximum deflection of the membrane. For example:

AV «(2 x 2 mm ² ) x 50% ^* (2 x 7.5 pm) / 2 = 15 x 10 ^{" 3} mm ³ (Gig 1) or AV / Active Area =, \ V / A =,: / 4 mm ² = 3.75 x 10 ³ mm (gig 2)

A general problem in the manufacture of miniaturized membrane loudspeakers is to achieve a flat progression of the sound pressure as a function of the frequency. The achievable sound pressure is proportional to the radiation impedance and the velocity of the membrane. In macroscopic terms, the diameter of the membrane is comparable to the acoustic wavelength. Here it applies that the radiation impedance is proportional to the frequency, cf. [6]. High-quality loudspeakers are often designed in such a way that the resonance f _{0 is} below the audible sound range (for reusable loudspeakers the respective resonant frequency lies below the lower edge frequency of the corresponding electric filter). For f »f ₀ the velocity of the membrane is proportional to / f. Overall, the expression p χ 1 then results for the frequency dependence of the sound pressure p. Thus, in this (simplified) consideration, a completely flat course of the sound pressure curve results. As soon as the diameter of the sound source / membrane is much smaller than the sound wave length to be generated, a radiation-impedance quadratic dependence on the frequency can be assumed, as described in [7]. This is true for MEMS speakers with membranes in the order of millimeters. If f _{0 is} assumed as above, then the dependence p f results for the course of the sound pressure curve. Low frequencies are reproduced in relation to the high frequencies with too low sound pressure. In quasi-static operation, the membrane velocity is proportional to f. The result for the sound pressure curve is the unfavorable dependence p χ f ³ for low frequencies. Miniaturized multifunctional systems for the human-computer or human-machine are available at different levels of integration. Stage 1: PCB hybrid integration

Sensors, actuators and electronic circuits, which were manufactured on different substrates, are combined on a common wiring carrier (here: printed circuit board).

Level 2: System-In-Package

At least two chips are connected in a special housing to form a system. In some cases, chip-on-chip bonds are also used. Often, silicon-based wiring substrates are also used (so-called "interposer technologies").

Stage 3: Wafer level hybrid integration and monolithic integration

Sensors, actuators, and electronic circuits, some of which are manufactured on different wafers, are interconnected at the wafer level. The individual chips of the bonded wafer stack are removed from the composite by means of appropriate singulation processes. In the monolithic integration sensors, actuators and electronic circuits are realized on a wafer. In both cases, the electrical connection of the elements by integrated interconnects or chip vias ("Through-Silicon Vias", short: TSV) realized.

An example of a far advanced hybrid integrated sensor-actuator system (stage I) are the so-called Hearables. The following components are already housed in the form of an in-ear headphone today: Loudspeakers (manufactured by precision mechanics), rechargeable battery, memory chip, CPU, red and infrared sensors, temperature sensors, optical touch sensor, microphones, 3-axis accelerator Sensor, 3-axis magnetic field sensor and 3-axis position sensor. Such a "system-in-a-package" approach is now used for Hearables by companies such as Bragi ("The Dash"), Samsung, Motorola and Sony. An example of a far advanced system-in-package sensor system (Stage 2) are so-called 9-axis sensors. Here are z. B. 3-axis acceleration sensor and 3-axis position sensor on a, a 3-axis magnetic field sensor on a second silicon chip and an electronic circuit realized on a third chip and housed in a common housing , A provider of such a system is z. For example, the company InvenSense (MPU-9150). Examples of monolithically integrated sensor systems are single- or multi-axis gyroscopes or acceleration sensors, pressure sensors and magnetic field sensors in which the sensor element and electronic functions are implemented in a single chip.

The monolithic integration offers great advantages in terms of size. While in the case of Leiterp! Atten hybrid integration for each device a separate housing is required and the system-in-package a relatively large housing, especially when combining several individual chips, this eliminates the need for additional space in the monolithic integration. In addition, due to the elimination of the complex, hybrid construction techniques, the production costs drop significantly, especially at high quantities.

In the case addressed here of miniaturized sound-generating (micro-loudspeakers) or sound-absorbing (microphone) MEMS components, monolithic integration with circuits or other actuator or sensor elements is today severely limited. The reason lies in the way the MEMS microphones or loudspeakers work. In both cases, a relatively large membrane is required, which is formed in the chip area. The chip area on the top and bottom is mostly needed for the air flow created by the movement of the membrane. There is thus no significant chip area available to integrate further functionalities. In principle, a possible enlargement of the chip surface is opposed, above all, by a disproportionately decreasing chip area. On the other hand, the manufacturing processes are often not directly compatible with the manufacturing processes of the CMOS circuit, which increases the complexity of the overall process. For these two reasons, therefore, further functionalities on one or more separate chips are nowadays realized in the acoustic components and the entire system is brought together via hybrid integration / system-in-package. At the same time there is a need to obtain the smallest possible space of MEMS converters to allow use in portable devices, such as headphones and in particular so-called in-ear headphones (in-ear headphones).

It would therefore be desirable to have a concept for improved MEMS converters which have a high degree of efficiency and at the same time a low space requirement. The object of the present invention is therefore to provide a MEMS converter and a method for producing the same, which can influence a volume flow of a fluid with a high efficiency and / or can be influenced by the volume flow with a high efficiency and with a allow small space requirements.

This object is solved by the subject matter of the independent patent claims.

The core idea of the present invention is to have recognized that the above object can be achieved in that a volume flow of a fluid can be influenced particularly efficiently by means of an element which is deformable in a plane of movement (in-plane) or the volume flow can deflect such element particularly efficient. This allows large areas of the deformable element, which can interact with the volume flow, with simultaneous small dimensions of a chip surface, so that overall an efficient MEMS converter device with a high efficiency is obtained. Furthermore, it has been recognized that integration of an electronic circuit for operating the MEMS into a layer of the layer stack makes otherwise unused semiconductor surfaces usable for the electronic circuit, which leads to a small installation space requirement of the device.

According to one embodiment, a MEMS converter for interacting with a volume flow of a fluid comprises a substrate having a layer stack with a plurality of layers. The substrate has a cavity in the Schichtstapei. The layers form a plurality of substrate planes. The MEMS transducer comprises an electromechanical transducer connected to the substrate in the cavity and has an element deformable in at least one plane of movement of the plurality of substrate planes. A deformation of the deformable element in the plane of motion and the volume flow of the fluid are causally related. The MEMS converter further comprises an electronic circuit which is arranged in a layer of the Schichtsta- pels. The electronic circuit is connected to the electromechanical transducer and configured to provide a conversion between deformation of the deformable member and an electrical signal.

According to a further embodiment, a device comprises a described MEMS converter, which is formed as a MEMS speaker, wherein the device is designed as a mobile music playback device or as headphones. According to a further embodiment, a health assistance system comprises a sensor device for detecting a vital function of a body and for outputting a sensor signal based on the detected vital function. The health assistance system comprises a processing device for processing the sensor signal and providing an output signal based on the processing, and comprises a headset comprising a described MEMS converter. The MEMS converter is implemented as a loudspeaker and comprises a wireless communication interface for receiving the output signal and is designed to reproduce an acoustic signal based thereon.

According to another embodiment, a method of providing a MEMS transducer for interacting with a volume flow of a fluid comprises providing a substrate comprising a layer stack having a plurality of layers forming a plurality of substrate planes and having a cavity in the layer stack. The method comprises generating an electromechanical transducer in the substrate so that it is connected to the substrate in the cavity and has a deformable in at least one plane of movement of the plurality of substrate planes element, wherein a deformation of the deformable element in the plane of motion and the Volume flow of the fluid causally related. The method further includes placing an electronic circuit in a layer of the layer stack so that the electronic circuit is connected to the electro-mechanical transducer and configured to provide a conversion between deformation of the deformable element and an electrical signal. Further advantageous embodiments are the subject of the dependent claims.

Preferred embodiments of the present invention will be explained below with reference to the accompanying drawings. Show it:

1 is a schematic perspective view of a MEMS converter according to an embodiment;

Fig. 2a is a schematic perspective view of a MEMS converter, a

Variety electromechanical transducer comprises, according to an embodiment; 2b is a schematic plan view of the MEMS converter of Fig. 2a according to an embodiment.

2c is a schematic perspective view of the MEMS transducer of FIG. 2a, in which the electromechanical transducers have a deformed state of a deformable element, according to one embodiment;

3 shows a schematic perspective view of a deformable element embodied as a bimorph, according to an exemplary embodiment;

4a is a schematic perspective view of a deformable member having three bimorph structures, according to an embodiment;

4b shows a schematic perspective view of the deformable element according to FIG.

4a in a deflected state according to an embodiment;

4c is a schematic plan view of an arrangement of two deformable elements, which are arranged adjacent to each other according to an embodiment;

5 shows a schematic plan view of a MEMS converter, in which the electromechanical converters have a changed configuration compared to the MEMS converter from FIG. 2 a, according to one exemplary embodiment;

6a is a schematic plan view of an electromechanical transducer, are arranged in the just-formed spring elements between plate elements and deformable elements, according to an embodiment;

Fig. 6b is a schematic plan view of an electromechanical transducer in which

Spring elements of deflectable ends of the deformable elements are arranged at an angle of less than 90 °, according to one embodiment;

Fig. 6c is a schematic plan view of an electromechanical transducer, in which the spring elements are arranged at an angle of more than 90 °, according to an embodiment; 6d shows a schematic plan view of an electromechanical converter, in which the substrate has a spring element adjacent to a deformable element, according to one exemplary embodiment; Fig. 6e is a schematic plan view of an electromechanical transducer in which

Plate elements have recesses, according to an embodiment;

7a is a schematic plan view of a deformable element which is connected to the plate element, according to an embodiment;

Fig. 7b is a schematic plan view of a configuration in which the deformable

Element is firmly clamped between the substrate and is formed, according to an embodiment; Fig. 7c is a schematic plan view of a configuration of the electromechanical

Converter, wherein the deformable elements have recesses in a central region, according to an embodiment;

Fig. 7d is a schematic plan view of a configuration of the electromechanical

Transducer in which a first deformable element and a second deformable element are arranged parallel to each other;

8a shows a schematic perspective view of a MEMS converter, in which the deformable elements are connected alternately to the substrate or to an armature element, according to an exemplary embodiment;

FIG. 8b shows a schematic plan view of the MEMS converter from FIG. 8a according to FIG

Embodiment; FIG. 8 c is a schematic perspective view of the MEMS converter of FIG. 8 a in a deflected state according to an embodiment; FIG.

FIG. 8 d shows a schematic plan view of the MEMS converter of FIG. 8 b in the deflected state according to an embodiment; FIG. 9 is a schematic perspective view of a stack comprising three MEMS transducers according to an embodiment;

10 shows a schematic perspective view of a detail of a MEMS converter in which deformable elements are arranged between sides of the substrate, according to an exemplary embodiment;

1 1 a is a schematic plan view of a section of a MEMS converter, in which the electromechanical transducer is arranged obliquely with respect to a lateral direction of the substrate, according to an embodiment;

Fig. 1 1 b is a schematic plan view of a detail of a MEMS converter which can be used as a pump; according to an embodiment; 12a is a schematic plan view of a detail of a MEMS converter, which can be used, for example, as a MEMS pump, in a first state;

FIG. 12b shows the MEMS converter of FIG. 2a in a second state; FIG. 13 shows a schematic view of two deformable elements which are connected to one another along a lateral extension direction, according to an exemplary embodiment;

14 is a schematic view of a stack comprising two MEMS transducers connected to each other and having a common layer according to an embodiment;

Fig. 15 is a schematic side sectional view of a deformable element, the two

Layers, which are spaced apart and connected to one another via connecting elements, according to an embodiment;

FIG. 16 is a schematic plan view of a deformable member disposed adjacent to an electrode according to an embodiment; FIG. 17a shows a schematic perspective view of a MEMS converter according to a further exemplary embodiment from a first side; FIG. 17b is a schematic view of the MEMS converter of FIG. 17a from a second side; FIG.

17c is a schematic perspective view of the MEMS Wandiers according to the

View in Fig. 17a, in which according to a further embodiment, openings are configured so that grid bars are arranged;

18a is a schematic perspective view of a MEMS Wandiers according to an embodiment in which adjacent to an electronic circuit, a functional element is arranged;

FIG. 18b shows a schematic perspective view of a MEMS converter that is modified relative to the MEMS converter of FIG. 18a in such a way that, according to one exemplary embodiment, an opening is arranged in a cover layer;

19a shows a schematic view of a layer for adapting pitch grids according to an exemplary embodiment;

19b is a schematic view of a use of an adaptation layer according to an embodiment,

FIG. 20 is a schematic block diagram of a MEMS system according to an embodiment; FIG.

Fig. 21 a shows a device according to an embodiment;

FIG. 21b shows a schematic block diagram of a further system according to an exemplary embodiment, which can be designed as a universal translator and / or as a navigation assistance system; FIG.

FIG. 22 shows a schematic illustration of a health assistance system according to an exemplary embodiment; FIG. FIG. 23 is a schematic plan view of a MEMS converter according to an embodiment having a plurality of electromechanical transducers with cantilevered beam elements; FIG. and FIG. 24 shows a schematic plan view of a MEMS converter according to an exemplary embodiment, which has a multiplicity of electromechanical transducers with bilaterally clamped beam elements.

Before embodiments of the present invention are explained in more detail in detail with reference to the drawings, it is pointed out that identical, functionally identical or equivalent elements, objects and / or structures in the different figures are provided with the same reference numerals, so that shown in different embodiments Description of these elements is interchangeable or can be applied to each other.

In the following, reference will be made to MEMS (microelectromechanical system). A MEMS transducer may include one or more electroactive components that cause a change in a mechanical component based on an applied electrical quantity (current, voltage, charge, or the like). This change may, for example, relate to a deformation, to a heating or to a tension of the mechanical component. Alternatively or additionally, a mechanical influence on the component, such as a deformation, a heating or a strain, can lead to an electrical signal or electrical information (voltage, current, charge or the like) that can be detected at electrical connections of the component. Some materials or components have a reciprocity, which means that the effects are mutually interchangeable. For example, piezoelectric materials may have the inverse piezoelectric effect (deformation based on an applied electrical signal) and the piezoelectric effect (providing electrical charge based on deformation).

Some of the exemplary embodiments described below relate to fully integrated and highly miniaturized systems for human-computer or human-machine interface applications and interaction, including applications in the area of "personal assistant", in which the acoustic interface is the focus. The embodiments relate to the integration of MEMS and CMOS. Some of the embodiments described below relate to a deformable element of an electromechanical transducer being configured to interact with a volumetric flow of a fluid. An interaction may include, for example, deformation of the deformable member caused by an electrical drive signal that results in movement, displacement, compression or decompression of the fluid. Alternatively or additionally, the volume flow of the fluid deform the deformable element, so that based on the interaction between the volume flow and the deformable element, a presence, a characteristic (pressure, flow velocity or the like) or other information relating to the fluid (such as Temperature) can be obtained. This means that a deformation of the deformable element along the lateral direction of movement and the volume flow of the fluid are causally related. For example, MEMS can be made in silicon technology. The electromechanical transducer may comprise the deformable element and other elements, such as electrodes and / or electrical connections. The deformable element may be configured to deform (macroscopically) along a lateral direction of movement, ie, an element or region may be movable along the lateral direction of movement. The element or area may, for example, be a bar end or a central area of a bar structure. Viewed microscopically, upon deformation of the deformable member along the lateral direction of movement, deformation of the deformable member perpendicular to the lateral direction of movement may occur. The embodiments described below relate to the macroscopic approach.

Embodiments may provide miniaturized speakers made in silicon, microphones and / or pumps which, based on their respective size, can produce the highest possible sound level, the highest possible sensitivity and / or the highest possible flow rate of the fluid. Other embodiments may provide a MEMS converter, a MEMS valve, and / or a MEMS dosing system.

Embodiments of the present invention may be used to generate airborne sound, especially in the field of audiophile sound. Exemplary embodiments thus relate to loudspeakers, in particular miniaturized loudspeakers, for example for hearing aids, headphones including in-ear headphones (in-the-ear headphones), headsets, mobile phones or like. The mutual causal relationship between the volumetric flow and the deformation of the deformable element also makes it possible to use it in loudspeakers. Embodiments thus relate to electroacoustic transducers. Embodiments make it possible to provide a highly miniaturized, multifunctional system which can be used in human-computer or human-machine interaction and can be produced cost-effectively in volume production. The core functionality, which is to be supplemented by additional functions, lies in the area of sound generation or sound recording.

1 shows a schematic perspective view of parts of a MEMS converter 10 according to one exemplary embodiment. The MEMS transducer 10 is configured to interact with a volumetric flow 12 of a fluid. The fluid may be a gas (such as air) and / or a liquid. For example, the fluid may be a medical solution, a drug, a chemical for a technical process, or the like.

The MEMS converter 10 has a substrate 14. The substrate 14 may comprise any material. By way of example, the substrate 14 may comprise a wood material, a metal material and / or a semiconductor material, for example a silicon material. The substrate 14 comprises a cavity 16. The cavity 16 can be understood, for example, as a recess or as an at least partially enclosed volume of the substrate 14. In the cavity 16, the fluid of the volume flow 12 can be arranged at least in some areas. The substrate 14 comprises at least one layer of material, such as a one-piece layer having the cavity 16, as may be obtained, for example, by milling or etching of a material, and / or when the cavity 16 is omitted in a generation of the substrate 14, so that the substrate 14 is generated around the cavity 16. The substrate 14 may also have a plurality of layers 15a and 15b, which may be advantageous, for example, in semiconductor manufacturing. Different structures, such as the presence and absence of the cavity 16, may be implemented in different layers of the substrate 14. Alternatively, the substrate may also have a higher number of layers, as explained below.

The MEMS converter 10 comprises an electromechanical transducer 18. The electromechanical transducer 18 is connected to the substrate 14. The electromechanical transducer 18 comprises a deformable element 22, which along a lateral movement tion direction 24 is deformable. For example, applying an electrical signal to the electromechanical transducer 18 may result in the deformation of the deformable member 22 along the lateral direction of movement 24. Alternatively or additionally, the volume flow 12, when it encounters the deformable element 22, may cause the deformable element 22 to perform the deformation so that an electrical signal from the electromechanical transducer 18 based on the volume flow 12 can be obtained , That is, the deformation of the deformable element 22 and the volume flow 12 are causally related. For example, the electromechanical converter 18 may comprise or consist of at least one, approximately two, piezoelectric layer. Both layers can be deformed by electrical voltage. The electromechanical transducer may comprise further elements, for example electrodes.

The MEMS converter 10 comprises an electronic circuit, not shown, which is arranged in at least one of the layers 15a or 15b of the layer stack. The electronic circuit, not shown, is connected to the electromechanical transducer 18, and is configured to provide a conversion between deformation of the deformable member 22 and an electrical signal. This means that the electronic circuit, not shown, can be used depending on the implementation of the MEMS converter for sensory and / or actuatoric control of the EMS converter 10. An arrangement of the electronic circuit in a cover layer of the substrate 14, such as the layer 15a, may allow to use a large area of the cover layer for the electronic surface, which allows a corresponding saving of chip area and / or space in other components, such as circuit boards, on which the MEMS converter 10 is mounted. An arrangement of at least parts of the electronic sounding in a cover surface of the layer stack may further allow the advantage that a simple contacting of the MEMS transducer with other electronic components is made possible.

The term conversion is to be understood here as the conversion of an input variable into an output variable. The electronic circuit may be configured to convert an electrical drive signal to a deflection of one or more deformable elements, ie, to perform an actuator drive, and / or to convert a deformation of one or more deformable elements into an electrical output, ie, one sensory evaluation or activation. For the conversion, the electronic circuit may include at least one of a digital-to-analog converter for converting a digital version of the drive signal. nals in an analog version of the drive signal and / or an analog-to-digital converter for converting an analog version of the electrical output signal into a digital version of the electronic output signal. In simple terms, the electronic circuit 17 can receive the drive signal In in an analog or digital form and convert it into an analog or digital signal Out suitable for the MEMS converter 10. For example. For example, the electronic circuit may be configured to convert the electrical drive signal In into a deflection of the deformable element of at least one electromechanical transducer. For this purpose, the electronic circuit may comprise a switching amplifier (so-called class-D amplifier). This can be designed to provide the signal Out as a digital pulse width modulated drive signal for the deformable element.

It should be noted here that the use of the term cover surface is related to the described layer stack, which describes, for example, outer layers of the stack. However, this should not be understood to mean that no further layers can be arranged, because it is possible to provide additional layers on the described stack, which cover the outer layers partially or completely. For example. it is possible to provide insulating layers, for example a semiconductor oxide or lacquers, but also other electrically functional layers.

The substrate 14 may include one or more openings 26a-d through which the volume flow 12 may pass from an environment of the MEMS transducer 10 into the cavity 16 and / or out of the cavity 16 into an environment of the MEMS transducer 10. A movement that the deformable element 22 performs during the deformation can be understood in terms of the substrate 14 as in the plane. The volumetric flow 12 can emerge from the cavity 16 at least partially perpendicular to the direction of movement 24 or can enter it, as illustrated, for example, for the volumetric flow 12 through the opening 26c or 26d. Simply stated, movement of the deformable element 22 in-plane may result in a volumetric flow 12 out-of-plane and vice versa. This means that the lateral direction of movement and / or the curvature of the deformable element can be in-plane with respect to the substrate.

The openings 26 c and 26 d are arranged perpendicular to the lateral movement direction 24 in the substrate 14. The deformation of the deformable element 22 along the lateral direction of movement 24 may result in a movement of at least one region of the deformable element 22 towards the opening 26 a, so that a partial cavity 28 ba- is reduced to the deformation on the deformation. A pressure of the fluid located in the subcavity 28 may be increased based thereon. Put simply, the fluid can be compressed. This can allow an outflow of the fluid from the Teilkavität 28 and the cavity 16. Through the openings 26 d and 26 c, the volume flow 12 can be obtained perpendicular to the lateral direction of movement 24.

A base area of the MEMS converter 10 may, for example, be arranged in an x / y plane. A large dimension of the MEMS transducer 10 along a z-direction that is perpendicular to the x-direction and / or the y-direction in space or a large dimension of the deformable element 22 along the z-direction may increase of the volumetric flow 12, while the base area of the MEMS converter 10 remains unchanged. An enlargement of the partial cavity 28 can lead to a negative pressure of the fluid in the partial cavity 28, so that the volume flow flows into the cavity 28 or 16 based on the deformation of the deformable element 22 perpendicular to the lateral movement direction 24.

The deformable element may have an axial extent, for example along the y-direction, which has a value in a range of at least 1 pm and at most 100 mm, preferably at least 100 pm and at most 10 mm, and more preferably in a range of at least 500 pm and at most 5 mm. The deformable element 22 may have an extent along the lateral movement direction 24, which has a value in a range of at least 0, 1 pm and at most 1000 pm, preferably of at least 1 pm and at most 100 pm, and particularly preferably in a range of at least 5 pm and at most 30 pm. The deformable element may have an extension along a lateral direction, which is arranged perpendicular to the lateral movement direction, for example along the z-direction, which has a value in a range of at least 0.1 .mu.m and at most 1000 .mu.m, preferably at least 1 pm and at most 300 pm, and more preferably in a range of at least 10 pm and at most 100 pm.

Fig. 2a shows a schematic perspective view of a MEMS converter 20 comprising a plurality of electromechanical transducers 18a-f. The electromechanical transducers 18a-f are connected to the substrate 14 and can each have a deformable element along the lateral movement direction 24, as described in connection with FIG. The substrate 14 includes, for example, a first layer 32a, a first spacer layer 34a, an intermediate layer 36, a second spacer layer 34b, and a second layer 32b arranged on top of each other in that order. According to further embodiments, one or more further layers may be arranged between two of the layers arranged as successively. According to further embodiments, at least one of the layers 32a, 32b, 34a, 34b and / or 36 has a multilayer structure. An electronic circuit 17, such as the electronic circuit described in connection with FIG. 1 may be partially or completely disposed in the layer 32b. Alternatively or additionally, the electronic circuit 17 may be arranged at least partially in one or more of the layers 32a, 34a, 36 and / or 34b.

The electronic circuit may be configured to convert an electrical drive signal In to a deflection of the deformable element by providing the electromechanical transducer with a signal Out based on the signal In. Alternatively or additionally, based on a deformation of the deformable element, a signal ln ₂ can be obtained, which can be converted by the electronic circuit into an electrical output signal Out ₂ . The conversion can in this case take place such that the electronic circuit 17 has at least one of a digital analog converter (ADC) and a digital / analog converter (DAC) or else an AC / AC converter or DC / DC converter. Based on this, the electronic circuit 17 may be configured to receive an input signal ln ₁ in an analog version and to convert them into a digital version to obtain the signal Outi. Alternatively, the signal In, even a digital signa! and the signal Out <, an analog, both signals can be lni and Out, digital or analog. Alternatively or additionally, the electronic circuit 17 may provide a conversion of the ln ₂ signal obtained from the electromechanical transducer, such as in an analog form, into the Out ₂ signal. The signal Out ₂ can be analog or digital. The electronic circuit 17 can thus be formed for converting a digital version of the drive signal in-i into an analog version of the drive signal Out, and / or an analog-to-digital converter for converting an analog version of the electrical output signal In, to a digital version of the electronic output signal (Out).

The electromechanical transducers 18a-f are formed and / or can be controlled by the electronic circuit 17, so that these are based on the volume flow 12 and / or based on a control partly towards each other and partially move away from each other.

For example, the electromechanical transducers 18a and 18b are configured to move away from each other while the electromechanical transducers 18b and 18c move toward each other. Partial cavities 38a-c are disposed between electromechanical transducers 18a and 18b, 18c and 18d and 18e and 18f, and subcavities 38a-c may increase based on the deformation of electromechanical transducers 18a-f. Between the electromechanical transducers 18b and 18c, and 18d and 18e, respectively, partial cavities 42a and 42b are arranged which can be reduced in size at the same time based on the movement or deformation. In a subsequent time interval, the deformation or movement of the electromechanical transducers or the deformable elements can be reversible, so that the volumes of the sub-cavities 38a, 38b and 38c decrease while volumes of the sub-cavities 42a and 42b increase.

The electronic circuit 17 may be arranged along a direction perpendicular to the plane of movement in which the electromechanical transducers move. If a location of the electronic circuit is projected into the plane of movement, then this may correspond to a location at which the deformable element is at least temporarily located during the deformation. This means that the deformable element can be located, for example, above or below the electronic circuit 17.

In other words, on the lower lid (first layer 32a), which partially or completely closes the chip on one side (for example but without limitation a lower side), a structured layer, the spacer layer 34a, may be arranged, for example as a spacer between the lower lid and the intermediate layer 36 arranged on the structured layer 34a can be used. On the structured layer 36, in turn, a structured spacer layer 34b may be arranged, which in its function as a spacer completely or partially corresponds to the spacer layer 34a and may have an identical or similar shape. Or its cavity can be partially or completely closed by the upper lid, the second layer 32b along the z-direction. FIG. 2 a shows the layer 32 b as a partially cut-away view in order to make elements arranged in the area of the cavity representable. In an x / y plane of the intermediate layer 36 may be arranged in pairs electromechanical transducers 18b and 18c and 18d and 18e, wherein such an arrangement can repeat several times along a spatial direction, for example along the x-direction. The electronic circuit 17 may be wholly or partly arranged in at least one of the covers 32a and / or 32b. It is also possible that the electronic circuit 17 also extends over several layers and, for example, is arranged partially in the layer 32a and the adjacent layer 34a or in the layer 32b and the adjacent layer 34b.

An arrangement of the electronic circuit wholly or partly in at least one of the lid 32a and / or 32b allows a space-saving and thus space-efficient arrangement of the electronic circuit. This is particularly advantageous in combination with a lateral, d. h., in-plane movable element possible. In contrast to perpendicular to this and out-of-plane moving elements, as is the case, for example, with loudspeaker membranes, it is possible to dispense with thinning out of the corresponding layer (for example for membrane formation) and / or covering the movable element with the membrane Lid can be arranged without affecting the functionality. In out-of-plane movements, the thinned membrane layer which at least partially forms the movable element would either be poorly suited for electronic circuit placement and / or an additional covering layer would degrade the performance of the device. In embodiments, the lid of the stack, which may also be covered by further layers, not a part of the movable element.

The substrate may have a plurality of openings 26 which are connected to a plurality of partial cavities 38a-c and 42a-b, wherein, for example, in each case an opening 26 may be connected to a partial cavity 38a-c or 42a-b. A volume of each subcavity 38a-c or 42a-b may be influenced by a deflection state of at least one deformable element 22 along the lateral movement direction 24. Adjacent sub-volumes may be complementarily complemented or reduced in size during a first or second time interval. In simple terms, a partial volume of a partial cavity 38a-c or 42a-b can be reduced, while an adjacent partial volume of a partial cavity 42a-b or 38a-c is increased.

In a region of one or more openings 26, bar structures 44 may be arranged. The bar structures 44 may be arranged so as to allow passage of the volumetric flow 12 in one or two directions, while reducing or preventing particles from entering or leaving the cavity or from the cavity. that is. For example, one form of the layers 32a, 32b, 34a, 34b, and / or 36 may be affected during a manufacturing process by selectively removing and / or selectively disposing or growing layers. For example, the bar structures 44 may be formed from the layers 34a, 36 and / or 34b based on a selective etching process. Further, during the manufacturing process, a shape of the cavities 38a-c and 42a-b may be influenced. For example, walls of one or more layers 32a, 32b, 34a, 34b, and / or 36 may be adapted to movement of the deformable elements of the electromechanical transducers 18a-f, for example, an at least approximately constant and / or small distance between the deformable elements and the To enable substrate 14.

Adjacent or on the bar structures or rod elements, a cover 43 may be arranged. The cover 43 may be disposed adjacent to the cavity 16 and / or separated therefrom by the rod members 44. The cover may comprise, for example, a flow material (mesh material), a foam material and / or a paper material. The cover may allow particles to enter the cavity 16 or exit the cavity 16 with a smaller diameter than a spacing between bar structures. Alternatively, the cover 43 may also be disposed adjacent or at an opening 26 which does not have the stop elements 44.

If a free end of the movable elements moves, for example in a curved path and / or a circular path, the substrate 14 may have a parallel or similar shape in a region in which the movable end moves. FIG. 2b shows a schematic plan view of the MEMS converter 20 from FIG. 2a. The electromechanical transducers 18a-f may, for example, be frictionally or positively connected to the substrate 14 on elements 46a-c. For example, one or more deformable elements of the electromechanical transducers 18a-f may be formed integrally with the elements 46a-c. The elements 46a-c may be disposed in a plane of the layer 36 or may be portions of the layer 36. For example, an extent of the deformable elements 22 of the electromechanical transducers 18a-f may be less than or equal to an extension of the layers 34a, 36, and 34b along the z-direction. That is, the deformable elements 22 of the electromechanical transducers 18a-f may be arranged and movable without contact with the layer 32a and / or 32b. Alternatively, at least one deformable element can also be deformed by contact. For example. between the at least one deformable element and an adjacent th layer, such as the layer 32a and / or 32b a low-friction, ie, a low coefficient of friction, layer may be arranged. The low-friction layer can enable a fluidic separation between partial cavities, as described, for example, for the wall structure 49. For example, a coefficient of friction may be 10%, 20%, or 50% less than a coefficient of friction of the layer 32a and / or 32b or the layer 34a and / or 34b. A frictional force between the deformable element 22 and adjacent layers may be less than a force needed to deform the deformable element 22. For example, based on a reduced frictional force, a force to be provided by an actuator may be lower, so that the actuator can be made less powerful. Alternatively or additionally, a sensitivity of the deformable element 22 to the volume flow 12 can be increased.

The electromechanical transducers 18b and 18c form, for example, side walls of the subcavity 42a (chamber). The movable members 22 of the electromechanical transducers 18a-f may be positively secured to the members 46a-c. Between a deflectable or movable end 52 of the deformable elements 22, a distance to the substrate 14 or to elements 48a-d of the substrate 14 may be arranged. The end 52 of the deformable element 52 can thus be arranged freely movable. One or more deformable elements 22 may, due to dimensional relationships, such as an expansion along the x direction in relation to an extension along the y direction, be simplified in a ratio of beam width to beam height, particularly far along the lateral direction 24. If the electromechanical converters 18a-f are designed, for example, as actuators, these actuators can be deflected when a corresponding signal is applied, ie. H. be curved so that, for example, the end 52 of the deformable element 22 moves on a curved path. According to the course of this path, at least one of the elements 48a-d may be formed such that a distance between and the end 52 remains approximately constant and / or small even when the deformable element 22 is deflected.

The MEMS converter 20 may have at least one wall structure 49. For example, a movement of the actuators, electromechanical transducers 18a-e or deformable elements can result in a chamber 42a-b being fluid-mechanically coupled to the adjacent ones due to fluid flows caused by the movement to fill the chamber 38a-c Chambers can occur. Based on the fluid-mechanical coupling, a fluid flow 57 between the partial cavities 42a and 38b occur. In order to reduce or avoid this direct coupling or the fluid flow 57, one or more partition walls (wall structures 49), which may possibly be immovable, may be arranged to separate adjacent chamber pairs 38 and 42. The wall structures can be easily realized, for example, in the respective places as an element formed continuously from the layers 34a, 36 and 34b. For example, such structures may remain disposed during a selective etching process. The wall structure 49 may also increase the mechanical stability of the EMS transducer 20 and may facilitate bonding between the individual layers. The at least one wall structure 49 may have openings or be designed to be completely continuous, which makes it possible to specifically modify attenuation arising from the inflow / outflow of the fluid from the chambers 38a-c and 42a-b, in particular for adjusting the width of the chambers Resonance curve or in general for adjusting the dynamic properties of the actuator chamber systems.

Considering FIG. 2b together with FIG. 1, a volume of the cavity 16 and / or the plurality of partial cavities 38a-c and 42a-b may be influenced by the layers 32a and 32b and side regions 53a and 53b of the substrate 14 be determined. The side portions 53a and 53b may be disposed between the layers 32a and 32b. The deformable elements of the electromechanical transducers 18a-c may be designed to execute a movement parallel to the first layer 32a and / or 32b at least in a section 55 of the lateral movement direction 24. This means that the deformable element can deform or move between the layers 32a and 32b.

A resonant frequency of a cavity or partial cavity may be affected by a geometry of the volume, by a frequency of driving the electromechanical transducers and / or by a mechanical resonance frequency of the deformable element (s). At least partially fluidly isolated (partial) cavities, for example by means of a wall structure 49, an arrangement of a low-friction layer, or based on an arrangement in different MEMS converters can have different resonance frequencies and / or be driven with different frequencies, for example by means of a control device. Based on different drive frequencies and / or different resonance frequencies, a multi-way speaker can be obtained. Resonant frequencies of cavities are used, for example, in the region of the cavity resonators or resonant cavities. Figure 2c shows a schematic perspective view of the ME S transducer 20 in which the electromechanical transducers 18a-f have a deformed state of the deformable element. For example, the deformable elements are deflected up to a maximum deflection. Compared to the illustration of Fig. 2a, a volume of the subcavity 42a is reduced based on the deformation (warp) of the deformable elements (beams). If, for example, a thickness (dimension along the z-direction or thickness direction) of the layers 34a and 34b (spacers) is low, flow of the electromechanical transducers 18a-f or the deformable elements can be negligible when the electromechanical transducers 18a-f move be. This may also apply to a distance between the electromechanical transducer 18a-f and the substrate, for example the element 48. Based on the deformation of the deformable element, a volume of the fluid, for example an air volume which may correspond to the volume difference of the partial cavities 42a in FIGS. 2a and 2c, can be delivered to an environment of the MEMS converter 20, for example in the form of the fluid. idstrom (volume flow) 12.

A dimension of the spacer layer 34a or 34b along the z-direction along which the first and second spacer layers 34a and 34b are disposed on the intermediate layer 36 may have a value in a range of at least 1 nm and at most 1 mm, preferably in a range of at least 20 nm and at most 100 pm or more preferably in a range of at least 50 nm and at most 1 pm. For example, if the dimension of the spacer layers 34a and 34b is small relative to a dimension of the electromechanical transducers 18a-f along the z-direction, then an amount of the fluid stream 57 that drives the electromechanical transducer 18a-f from a first side to a second side (e.g. from a positive x-direction to a negative x-direction or vice versa) flows around while the deformable element deforms, being smaller than an amount of the volume flow 12 in the cavity. The flow stream 57 may be based, for example, based on at least partial removal of the spacer layers 34a and / or 34b in a region in which the electromechanical transducer 18a-f is moving. In simple terms, based on the distance between the electromechanical transducer and adjacent layers, fluid flow around movable elements may result (fluidic losses). These may be low compared to the fluid stream 12. examples For example, they may be less than the volume of volume divided by the value of 10, divided by the value of 15, or divided by the value of 20.

The electromechanical transducers can move in pairs towards and away from each other. For example, the electromechanical transducers 18a and 18b can move away from each other in pairs relative to the state in FIG. 2b and move in pairs in a subsequent time interval. At the same time, for example, the electromechanical transducers 18b and 18c may move in pairs toward or away from each other. Such a pairwise complementary movement of electromechanical transducers, which is possible even when the transducers are not arranged adjacent to one another, can result in an at least partial but also complete compensation of inertial forces, so that a small amount of vibration or no vibrations is received in the MEMS converter or is transmitted from the MEMS converter to the environment.

In other words, it may be a special feature of the chamber approach described so far that the actuators always move in opposite directions to and fro in pairs. Thus arise (with corresponding careful design of the two each chamber wall limiting active bending actuators) no vibrations z. B. when used as a hearing aid or in-ear headphones (in-ear headphones) would be annoying.

The fluid flow 12 may, for example, pass through the opening 26a and / or 26b. The openings 26a and 26b may be formed the same or adapted to a geometry of the adjacent Teilkavität 38a and 42a. The opening 26a may, for example, along a axial direction (about the y-direction) have a variable Ouerschnitt, about a dimension along the x-direction. The dimension of the opening 26b along the x-direction may decrease in a direction toward an interior of the MEMS transducer 20, ie towards the cavity or sub-cavity 42a. Alternatively or additionally, the opening 26 along a further direction, such as a z-direction (thickness direction) perpendicular to the axial direction y have a variable dimension or a variable Ouerschnitt. The variable cross-section may decrease from an outside of the MEMS transducer 20 in a direction toward the cavity 16. A tapered cross-section or diminutive dimension of the opening 26 from the exterior of the MEMS transducer 20 toward the cavity 16 along one or more directions x and / or z may be referred to as a funnel-shaped opening. The optionally funnel-shaped opening 26b can be used as a device for impedance matching. An impedance matching may be advantageous, for example, when using the MEMS converter 20 as a loudspeaker. An embodiment or geometry of the opening 26b may be carried out analogously to macroscopic speakers with dimensions of several centimeters. A shape of the opening 26b may allow the actual sound radiation to be defined by the outer surface of the funnel. The opening 26b may, for example, be formed continuously in the structured layers 34a, 36 and 34b. A bar grating 54, which comprises at least one bar element 44, may have openings or gaps between bar elements 44 and / or between bar elements 44 and the adjacent substrate. The gaps may be formed so that the fluid can flow through them.

The bar grating 54 may provide protection against particle penetration into the cavity of the MEMS transducer 20. A width of the openings of the bar grating 54, d. H. a distance between rod elements 44, can be designed so that the fluid flow 12 is fluidically influenced to a desired degree or is unaffected. For example, or ideally, the distance between the rod elements 44 may be smaller than the smallest gap distances in the MEMS converter 20, so that the rod grid can filter a large number of or even all relevant particles. For example, a gap distance may describe a distance of a deformable element 18a-c to a layer 32a or 32b. The distance between the rod elements 44 may for example be less than 5 pm, than 1 pm, as 0, 1 pm or 0.05 pm.

Dimensions of the rod elements 44 along the spatial directions can be implemented in such a way that the rod elements 44 do not produce any resonances in the area of the audible sound, i. H. in a frequency range of at least 16 Hz and at most 22 KHz. Although the rod members 44 are illustrated as being disposed on an outer side of the MEMS transducer 20, such as in a region where the opening 26a or 26b has a maximum dimension along the x direction, one or more rod members may also be attached another location of the opening 26a or 26b, for example in a tapered region of the opening 26a or 26b.

By the deformation of the deformable elements, the volume of a Teilkavität 42 a can be reduced. During a same time interval, a volume of the chamber (subcavity) 38a may increase. The subcavity 38a can, in the same or a similar manner as the subcavity 42a, be provided via a funnel-shaped opening 26b and / or a bar grate. ter 54 comprising one or more rod elements 44 to be connected to the environment of the MEMS converter 20. Electromechanical transducers 18a-f may be configured to be driven at a frequency different from each other or to have a resonance frequency different from each other. A volume of each subcavity may vary at a different frequency or at least partially equal frequencies.

The opening 26a and the opening 26b may be disposed on or in opposite sides of the ME S converter 20 in space. For example. For example, on each side having the opening 26a or 26b, the fluid stream may be ejected 12 or sucked in by means of the partial cavities 42a or 38a or a plurality of such partial cavities. This means that the fluid flow 12 can be generated in opposite directions. For example, in a first time interval, the volume flow 12 can be expelled from the opening 26a in a negative y-direction and be sucked into the sub-cavity 38a. In a second time interval these directions can be reversed. A current short circuit along the MEMS converter 20 can thus be prevented or excluded.

The deformable elements (beams) of the electromechanical transducers 18a-f may be configured to warp in accordance with an externally applied signal. A frequency with which the curvature takes place can be a frequency with which the volume flow 12 is generated and / or oscillates and thus influence or determine a sound frequency. An amplitude of the oscillation determined via the supplied signal can influence or determine an amplitude of the volume flow 12 at one or more (resonance frequencies) and consequently have an effect on the sound level.

Also, at least one chamber (cavity or Teilkavität) act as a sensory element and another chamber act as an actuator element. This means that the MEMS converter can comprise at least one sensory and at least one actuatoric deformable element. The movement of the bars is detected and evaluated. Thus, for example, the electromechanical transducers 18a and 18b can be actuated as actuators, while the electromechanical transducers 18c and / or 18d can be used as sensors for detection within the fluid. For detection electrostatic (capacitive), piezoelectric or piezoresistive sensor elements can be integrated. Such an element can be used as a microphone or pressure sensor. the. Such an integrated microphone or such a pressure sensor can also be used for controlling and controlling the characteristics of the loudspeaker chambers (actuators) or ultrasound transmitter chamber or pump chamber. For this purpose, a corresponding electronics as control circuit / control circuit is used.

Hereinafter, further embodiments of the electromechanical transducer or actuators will be explained. Although the MEMS transducer 20 has been described as having an undeflected state with undetachable deformable elements, the states may also be mutually interchangeable. That is, in a first, unactuated state, the deformable elements may be deformed or curved and may deform to a less curved, more curved, or even state based on a drive signal.

Although the above explanations explain that an electrical signal is applied to the MEMS converter 20, such as from a control device, the volumetric flow 12 may also lead to deformation of the deformable elements, wherein the deformation is obtained by means of an electrical signal at the MEMS converter 20 can be, d. H. the MEMS converter 20 is also configurable as a sensor. In the following, reference will be made to advantageous developments of the deformable element. One or more electromechanical transducers may comprise deformable elements according to the developments described below.

Fig. 3 shows a schematic perspective view of a deformable element 30, which is designed as a bimorph. The deformable element 30 has a first layer 56 and a second layer 58, which are at least in places, advantageously over the entire surface, firmly connected to each other. The first layer 56 and the second layer 58 are designed to deform differently, for example expand or contract, based on a mechanical, physical or chemical influence. For example, the layers 56 and 58 may have mutually different thermal expansion coefficients. Alternatively, or additionally, the layer 56 or layer 58 may be configured to expand or contract based on an electrical signal applied to the corresponding layer. For example, this layer may comprise piezoelectric materials. Mutually different contractions or extensions of the layers 56 and 58 may result in deformation of the deformable element 30 along an actuation direction 59 or 59 '. The actuation direction can be arranged parallel to the lateral movement direction 24. The actuation direction can be a direction along which the deformable element 30 can be deflected by applying a positive electrical voltage.

Alternatively or additionally, it is also possible to utilize a deformation along a further lateral movement direction 24 ', which is based for example on the basis of a transverse contraction or transverse expansion of the deformable element 30 or the contraction or expansion of one of the layers. That is, the deformable member 30 may be formed to curl with its beam structure along an axial direction (such as the y-direction) of the beam structure. This can be done based on a back-and-forth movement, ie along the lateral movement direction 24 and along an opposite direction.

In other words, the bimorph can correspond to a bar consisting of two layers. The layers are arranged, for example, in one direction (for example, vertically) to each other. A passive layer (eg, layer 56) may be firmly bonded to an active layer (eg, layer 58). By applying a suitable signal, a mechanical stress can be generated in the active layer 58, which leads to the contraction or expansion of the layer 58. A direction of change in length of the layer 58 may be selected so that the bimorph bends laterally in one (contraction) or other (expansion) direction.

FIG. 4a shows a schematic perspective view of a deformable element 40, which has three bimorph structures 30a-c, as described in connection with FIG. A schematic arrangement of the deformable element 40 in space along the x, y, and z directions is illustrated by way of example (but not limitation) as the deformable element 40 may be disposed in the EMS transducer 10 or 20, for example. The deformable (sub) elements 30a-c may have different dimensions from one another, for example along the x, -y or z-direction. For example, the deformable elements 30a and 30c may have an equal extent along the y-direction. The actuation directions 59a-c of the deformable elements 30a-c may, for example, be arranged alternating or having a mutual orientation, for example in the positive / negative / positive x direction. Simplified be understood that the deformable elements 30a and 30c have an equal length. The deformable member 30b may have a different length. For example, a length of the deformable element 30b may be twice as long as the comparable length of the element 30a or 30c. Between the deformable elements 30a-c further elements may also be arranged according to further exemplary embodiments, for example spring elements.

A direction along which the deformable elements 30a-c deflect upon application of an equal or comparable magnitude (such as an electrical voltage sign) may be alternating along the length of the deformable element 40. This allows an alternating curvature course. Although the deformable member 40 is illustrated as comprising three deformable members 30a-c, two deformable members or more than three deformable members 30 may be disposed. 4b shows a schematic perspective view of the deformable element 40 in a deflected state. The layers 58a-c are, for example, contracted so that a multiple curvature results along an axial course (y-direction).

In other words, three bars shown in Fig. 3 may be arranged juxtaposed in the direction of their extension. This can be done so that a first beam and a third beam (30a and 30c) with a corresponding signal has a curvature in a first direction and the second Baiken (30b) has a curvature in the other direction. Thus, an actuator can be obtained which, starting from its elongated shape, as shown in Fig. 4a, without applied signal S-like deformed with a corresponding signal, as shown in Fig. 4b. The configuration with Signa! and without signal is mutually interchangeable. For example, the deformable elements 30 may include a lead or bias that results in a reduced curvature or straight extension of the deformable member 30 and / or 40 based on the applied signal. For example, it can be assumed that the bends of the individual beams 30a-c are identical except for the sign, and a length of the first and third beams 30a and 30c corresponds to approximately one quarter of an overall length of the deformable element and wherein a length of the middle beam 30b in about one half of the length of the deformable element 40 corresponds. 4c shows a schematic plan view of an arrangement of two deformable elements 40a and 40b clamped on both sides, which are arranged adjacent to one another, so that the partial cavity 38 is arranged between the deformable elements. The solid lines show, for example, an actuated state of the deformable elements 40a and 40b while the dashed lines show an unactuated state, this description of the deformable elements being mutually interchangeable, since the unaktuierte state can take any form through the production.

The deformable elements 40a and 40b may be formed to have a curvature in the unactuated state. Further, the deformable members 40a and 40b may be formed of three segments 30a-1 to 30c-1 and 30a-2 to 30c-2, respectively, which perform mutual curvature during the actuation. Each segment, such as the middle segment 30b-a or 30b-2 may also be formed of two or more segments. Compared with the representations of FIGS. 4a and 4b, the segments 30a-1, 30b-1 and 30c-1 may have a different length to each other and to each other segment. The length may be adaptable to a desired shape to be obtained upon actuation. The S-shaped actuators have the great advantage that not only a large planar filling factor can be achieved with them, but they can also be clamped on two sides. Due to the double-sided clamping, a technically unavoidable deflection of the beams due to stress gradients is significantly reduced. Thus, the distances to the lower and upper lid of the substrate can be kept very low, which reduces the flow / pressure losses disproportionately and thus not only significantly increases the efficiency of speakers, ultrasonic transducers, microphones and pumps, but their proper functioning only possible. According to further embodiments, only one of the deformable elements 40 may also be arranged, for example in the MEMS converter 10.

5 shows a schematic plan view of a MEMS converter 50, in which the electromechanical converters 18a-c have a changed configuration compared to the MEMS converter 20. The electromechanical transducers 18a-c each include first and second deformable members 22a and 22b, 22c and 22d and 22e and 22f, respectively. The deformable elements are arranged opposite one another. Deflectable ends of the beam elements are arranged facing each other. Areas where the deformable elements 22a-f are connected to the substrate are arranged facing away from each other. The electromechanical transducers 18a-c each include a plate member 62a-c connected to the respective deformable members 22a and 22b, 22c and 22d and 22e and 22f, respectively. The respective plate member 62a-c may be connected to the deflectable ends of the respective deformable members 22a-f.

The deformable elements 22a-f may be wholly or partially designed as a deformable element 30 or 40 or have a different configuration. Different hatching of the deformable elements 22a and 22b, 22c and 22d and 22e and 22f indicate that the deformation of the respective deformable element is different from each other. The deformable elements of an electromechanical transducer 18a-c may be arranged to perform a deflection of the deflectable ends along a same spatial direction, independently of a respective embodiment of the deformable element 22a-f.

For example, from the undeflected state illustrated in Figure 5, a drive may cause the deflectable ends of the deformable elements 22a and 22b to be made along a positive x-direction. Furthermore, an activation of the deformable elements 22c and 22d can cause a deflection of the respective deflectable ends along a negative x-direction. This allows the plate members 62a and 62b to move toward each other during this drive so that the subcavity 42a is reduced based on the movement of the plate members. Alternatively or additionally, a negative pressure in the cavity 42a may cause the plate members 62a and 62b to move toward each other, so that deformation of the deformable members 22a-d is obtained. Alternatively or additionally, it is also conceivable that one or more deformable elements 22a-d are made electrically passive. For example, an electrical potential may be applied to one or more plate members 62a-c so that an attractive or repulsive force can be obtained between the plate members 62a and 62b based on an electric potential of the plate members 62a and 62b, which movement the plate elements 62a and 62b and thus causes deformation of the deformable elements 22a-d. Alternatively or additionally, the deformable elements 22c-f and / or the plate elements 62b and 62c can be actuated simultaneously or with a time delay in order to obtain a deformation of the deformable elements 22c-f and a change in the volume of the partial cavity 38a. In other words, Fig. 5 shows a variant of the configuration shown in Figs. 2a-c, in which four bending beams 22a-d and 22c-f are used for the narrowing or widening of each chamber (cavities 42a and 38a). In connection with FIGS. 2a-c, this is described based on in each case two bending beams (deformable elements). Fig. 5 shows a non-actuated state. The actuated and non-actuated states are mutually exchangeable. Thus, in general, any controllable deformable element can be deformed when the signal is not present and its signal-dependent change its deformation, including the achievement of a stretched (undeflected) state is a special case.

Vertically (eg along the y-direction) bending beam, such as the deformable elements 22a and 22b and 22c and 22d, respectively, may be connected to each other via a bendable web comprising the elements 64a and 64b. In a central region of the web thus obtained, a relatively stiff extension, the element 66, may be arranged. On this turn, the plate member 62b may be arranged, which is designed to be stiff or stiff as possible. Upon application of a corresponding signal, the plate members 62a-c may move toward or away from each other in parallel to reduce or increase volumes of sub-cavities. The parallel movement of the plate members may allow the volume of the subcavity 42a to be, in the limit, zero, that is, the plate members 62a and 62b are in contact. Compared with a configuration as described in connection with FIGS. 2a-c, such an arrangement can provide a volume flow of the fluid which is significantly higher than the volume flow of the MEMS converter 20. When the volume of the partial cavity 42a is reduced, this can be achieved Volume of Teilkavität 38b be increased according to or at least based thereon. The supply of the fluid, as described in connection with the MEMS converter 20, can take place through an opening 26a, 26b or 26c. The elements 64a and 64b may also be referred to as spring elements. The deformable elements (bending beams) 22a and 22b may be designed to warp to the right (positive x direction) when the signal is applied. Deformable elements 22c and 22d may be designed to skew to the left when the signal is applied (negative x-direction). Both types of bars (hatches of the deformable elements) may be designed so that they bend, for example, in a first signal as in connection with Figs. 3 or 4 and warp in the opposite direction at a second signal. In this case can both the constriction and the expansion of the chamber (partial cavity) to the original size regardless of the mechanical restoring force due to the bending of the beams can be achieved. The first and second signals may be, for example, a positive and a negative electrical voltage. If, for example, FIG. 3 is considered, the layers 56 and 58 can also be active layers or a further active layer can be arranged on the layer 56 on a side facing away from the layer 58, the two active layers being addressed separately from one another can to get a deflection in one direction or the other. A volume between two opposing deformable members, such as the deformable members 22c and 22d and the plate member 62b joined thereto, may also change upon movement or deformation of the flexures. For example, the plate member 62 may be rigid. To allow for improved pressure equalization, the deformable members 22c and / or 22d and / or connecting members 64 and 66 connecting the plate member 62b to the deformable members 22c and 22d may be locally thinned or thinned to provide a local flow channel. This can be done, for example, by additional structuring or etching. The connecting elements 64a, 64b and 66 may be arranged in a T-arrangement. The connecting element 66 may have a high rigidity compared to the elements 64a and 64b. Thus, during deformation of the deformable members 22c and 22d, the members 64a and 64b may preferably deform to facilitate rectilinear movement of the respective panel member. In the following, advantageous embodiments will be described with reference to FIGS. 6a-e, in which the plate element 62a or 62b is connected to respective opposing deformable elements 22a and 22b or 22c and 22d.

Although subsequent embodiments refer to a compound of the plate members with the deformable elements, which are each configured the same, different electromechanical transducers and / or connections of individual deformable elements to a plate element can be performed different from each other. The details described below do not describe any concluding advantageous developments and may be implementable on their own or in combination with one another or with other advantageous embodiments. 6a shows a schematic plan view of a configuration in which spring elements 68 that have just been formed are arranged between the plate element 62a or 62b and the deformable elements 22a and 22b or 22c and 22d. The spring elements 68 may be formed from a material of the deformable elements 22a-d or a material of the plate elements 62a or 62b and / or be formed integrally with one or more of these elements. For example, the spring members 68 may be at right angles to the plate members 62a or 62b.

Fig. 6b shows an alternative configuration in which spring elements 68 'of deflectable ends of the deformable elements are arranged at an angle α of less than 90', for example 30 or 40 °. This allows for a greater spacing of the contact points on the plate member 62a as compared to the configuration of Figure 6a, which may result in reduced deflection of the plate member 62a during movement.

Fig. 6c shows a configuration in which the spring elements 62a are arranged at an angle α of more than 90 ^' . This can, for example, lead to reduced restoring forces of the spring elements 68, if the configuration, as shown in FIG. 6a, is used comparatively.

FIG. 6 d shows a configuration in which the configuration from FIG. 6 a is modified such that in regions of the substrate 14 adjacent to which the electromechanical transducer 18 a is arranged or the respective deformable element is connected to the substrate 14, a spring element 72a or 72b is arranged.

The spring element 72a and / or 72b may be at least partially determined, for example, by a recess (cavity) 74a or 74b in the substrate 14. This means that, for example, through the recesses 74a or 74b, a rigidity of the substrate 14 can be locally reduced, so that the spring elements 72a and 72b are formed. Although recesses 74a and 74b are shown extending beyond adjacent deformable elements 22a and 22c, 22b and 22d in substrate 14, protrusion 74a or 74b may also be adjacent to, or adjacent to, a deformable element be arranged a plurality of deformable elements. Alternatively, the substrate 14 may also have a plurality of recesses or spring elements. In other words, Fig. 6d shows a configuration in which a further structure in the form of a spiral spring (spring elements 72a and 72b) to which the deformable elements (beams) are attached, can lead to a further reduction of the tensile stress. Such flexural spring elements may for example also be integrated in the rigid plate, as shown in the configuration of FIG. 6e and described in connection with the recesses 76a-d. These elements can deform S-shaped in the case of deflection of the beams and reduce the tensile load on the rigid plate.

FIG. 6e shows a configuration of electromechanical transducers 18a and 18b in which the plate members 62a and 62b have recesses 76a-d adjacent a region where the. FIG. 6d is compared with the configuration described in connection with FIG Plate elements 62a and 62b are connected via the spring elements 68 with the deformable elements. A distance between the recesses 76a-d and a deformable elements facing side of the plate members 62a and 62b, respectively, can influence a rigidity of the plate member 62a or 62b in this area. The recesses 76a-d allow for reduced restoring forces acting on the deformable elements 22a-d.

In other words, FIGS. 6a-e show variants for an embodiment of the movable elements or the electromechanical converters. These differ from a design, as described in connection with FIG. 5, for example, or in particular in that the elements 64a or 64b shown in FIG. 5 have been fused with the stiffening 66 toward the spring elements 68. The configuration according to FIG. 6a can have a higher rigidity against parasitic tilting of the plate elements 62a or 62b about an axis perpendicular to the plane of the drawing (x / y plane). The same applies to the configurations according to FIGS. 6b and 6c. All three configurations also allow for greater deflections of the flex beams as compared to the configuration of Figure 5. There, the member 64a and 64b, respectively, may be under tension at deflection of the beams, which increases with increasing displacement into increasing mechanical strength Resistance can result for the beam deflection of the deformable elements. In the variants according to FIGS. 6a-c, the mechanical connection of the two deformable elements can be made significantly softer (less rigid), since the respectively connecting spring elements 68 can react with a bending, which with a corresponding design of these elements has a significantly lower mechanical resistance can represent. The connecting elements / springs 68 and / or the elements / springs 64a-b described in connection with FIG. 5 may also have a curved or meandering shape. This allows for increased flexibility in a preferred direction. The configurations as described in connection with FIGS. 6d and 6e allow a reduction in the tensile load which would lead to an effective stiffening of the deformable element. The configurations described in FIGS. 6a-e neglect inlet and outlet openings 26. If these openings are arranged, recesses or spring elements in the substrate in regions in which the opening is arranged can be dispensed with. Alternatively or additionally, one, several or each of the spring elements 72a, 72b obtained by at least one recess and / or in the plate elements 62a or 62b may be realized based on two or more separate and independent spring elements.

FIGS. 7a-c described below describe examples of possible arrangements of deformable elements and plate elements.

FIG. 7 a shows the deformable element 40 which is connected to the plate element 62. The plate element 62 may for example be arranged directly on the deformable element 40.

FIG. 7 b shows a configuration in which the deformable element 40 a is firmly clamped between the substrate 14 and is formed to deform along the lateral direction 24. Between the deformable element 40 and the plate element 62, two further deformable elements 40b and 40c are arranged, the ends of which can be connected to one another. Based on the connections, the deformable elements 40b and 40c may be aligned with each other such that a bulge of the respective deformable element 40b or 40c faces away from the other deformable element. The deformable elements 40a-c can, for example, be actuated jointly or react together to the volumetric flow of the fluid, wherein, for example, joint control of the deformable elements 40a-c increases the travel, ie, enlarges the path around which the plate element 62 is deflected lead. This means that between the deformable element and the plate element at least one further deformable element can be arranged, which is designed to increase a travel of the deformable element in the case of a common control with the deformable element. Fig. 7c shows a configuration of the electromechanical transducer 18 in which the deformable elements 40a-c in a central region recesses 70a or 70b, the fluidic coupling of a volume 82 between the deformable elements 40b and 40c with another Teilkavität, for example, the Teilkavität 38a. The deformable elements 40a, 40b and / or 40c may each be made in two parts to provide the recesses 78a and 78b. Alternatively or additionally, the recesses 78a and 78b may be formed as recesses, which are enclosed along a thickness direction (z-direction) of further material of the deformable elements 40a, 40b and 40c.

In other words, Fig. 7a shows a S-shaped bending beam actuator configuration according to Fig. 4, in which a connection to the bending beam is arranged in the center of the rigid plate. To increase the deflection, the bending actuators can be arranged several times in succession (serially). FIGS. 7b and 7c show diagrammatically an arrangement of three serially connected S-actuators. According to further embodiments, two S-actuators (deformable elements 40) or more than three actuators can be connected in series. The hatchings of the deformable elements in FIGS. 7a-c are shown, for example, in accordance with the hatching as selected in FIG. Hatching that differs from one another can mean a different direction of curvature of the respective sections. Fig. 7c shows a configuration having an opening in the center of the S-shaped actuators (recesses 78a and 78b) which allows for improved ventilation of the gap (cavity 82).

Fig. 7d shows a configuration of the electromechanical transducer in which a first deformable element 40a and a second deformable element 40b are arranged along the y-direction parallel to each other. This allows an increase in the force with which the plate member 62 is deflected. Ends of the deformable elements may be connected to each other or disposed together on the substrate. Alternatively, two or more deformable elements 40a and 40b may also be arranged parallel along another direction, for example along the z-direction (thickness direction). Alternatively or additionally, a series connection and a parallel connection of deformable elements can also be combined.

Movable elements can hit another moving element or element at high or high deflection. This can lead to sticking. The movable elements or the fixed elements may preferably be equipped with spacer belts. bollards, which make it possible to significantly reduce the contact area and thus reduce or avoid sticking. Instead of so-called bollards, small structures designed as spring elements can also be arranged. In addition to avoiding sticking, the impulse can be reversed when two elements strike, which can reduce or avoid energy losses or improve the dynamic behavior of the actuators.

8a shows a schematic perspective view of a MEMS converter 80, in which the deformable elements are connected alternately to the substrate or the intermediate layer 36 or to an anchor element 84 which is connected to the substrate. For example, the deformable element 22a in the regions 46 and 48 of the intermediate layer 36 is fixedly connected at ends to the substrate and configured to perform an S-shaped movement, as exemplified in connection with the deformable element 40. The adjacently disposed deformable element 22b is connected to the anchor element 84. The anchor member 84 is disposed in a center portion of the deformable member 22b, and may be connected to the spacer layer 34a or the layer 32a with the same. This means that the substrate can have an anchor element. Side walls of the intermediate layer 36, which are disposed adjacent to movable ends of the deformable members 22a or 22b, may be formed based on a movement shape of the deformable members 22a and 22b, respectively.

FIG. 8b shows a schematic plan view of the MEMS converter 80, wherein the spacer layer 34b and the layer 32b are not shown by way of example. The MEMS 80 includes the rod members 44 in areas of the openings 26. The areas 48 may include the spring members 72a-c. The regions 48 are shown by way of example as a plan view of the intermediate layer 36. The anchor member 84 may be integrally molded with the deformable member 22b and / or a layer of the substrate. However, as shown in FIG. 8, the anchor member 84 may extend beyond the deformable member 22b along the z-direction to interconnect the layers 32a and 32b. This allows a reduced susceptibility to vibration of the layers 32a and 32b. Alternatively, the anchor element 84 may also be formed from another piece and / or from a different material, such as the mechanically deformable element 22b. The neighboring For example, the formable element 22a is fixedly connected on both sides to the substrate in the regions 48 or 46, for example by positive or non-positive engagement.

For example, a distance 85 between bar elements 44 may be less than 1 pm, than 0, 1 pm or 0.05 pm.

The anchor member 84 may be disposed in a center portion of the deformable member 22b. The middle region may, for example, comprise a geometric center of gravity of the deformable element. The middle region can be, for example, the bar segment 30b of the deformable element 40.

FIG. 8c shows a schematic perspective view of the MEMS converter 80 in a deflected state. FIG. Outer portions of the deformable member 22b may have moved in a direction toward the deformable member 22a with locations of the outer ends of the deformable member 22a remaining substantially unchanged. A center portion of the deformable member 22a may have moved in a direction of the deformable member 22b with a location of the center portion of the deformable member 22b based on the anchor member 84 substantially unchanged.

FIG. 8d shows a schematic plan view of the MEMS converter 80 in the deflected state, as described in FIG. 8c. The volume of the cavity 42 is reduced compared to the view of FIG. 8b, whereas a volume of the cavity portion 38 is increased. The spring element 72a may lead to a reduced introduction of force into the deformable element 22a, but may not be arranged. Between the beam structures of the first electromechanical transducer and the second electromechanical transducer or between the actuators 22a and 22b may be arranged a first Teilkavität 42, which is adjacent to an opening 26 of the substrate. In other words, FIGS. 8a and 8b show a schematic 3D representation or a plan view of a variant in which a chip area of the MEMS converter can be exploited very efficiently. As in the basic configuration, as described in connection with FIGS. 2a-c, exclusively or predominantly bending actuators can be used, ie the additional rigid plate element can be dispensed with. The chamber 42 is bounded by two undeflected S-actuators 22a and 22b, as illustrated in FIG. 8a. The left (negative x-direction) limiting S-actor 22a can with its two Ends in the drawing above or below (ie along the positive or negative y direction) to be connected to the rest of the device. The right limiting S-actuator 22b may be attached to a post (anchorage) 84. The two ends of this S-actuator can be freely movable. The post 84 may be fixedly connected to the upper and lower decks 32a and 32b, respectively. When the signal is applied, both actuators bend S-shaped. The spring element 72a, which is concealed in FIG. 8a and is influenced by a recess, can serve for strain relief. The spring element is arranged in the drawing plane of FIG. 8 b along the lateral movement direction 24 in the element 48, so that the spring element 72 a is firmly clamped along the lateral movement direction 24. The spring element 72a, as shown for example in Fig. 8, based on the spacer layers 34a and 34b have a fixed connection thereto and also be clamped. Alternatively, the layers 34a and 34b may also be patterned such that the spring element 72a has no contact with the spacer layer 34a and / or 34b and thus may have a higher compliance.

As shown in Figs. 8c and 8d, the bulbous bulges of the S-actuator 22a may be moved toward the post 84 so that the center of the S-actuator 22a almost contacts the center of the S-actuator 22b. At the same time, the free ends of the S-actuator 22b have moved in the direction of the fixed clamping of the S-actuator 22a, so that they also almost touch each other. The aktuierte form of the two S-actuators can be approximately the same or identical, so that the chamber 42 can close practically or almost completely with sufficient deflection of the actuators. The original volume of the chamber 42 can thus be used completely for the generation of the volume flow or for its detection. To the same extent as the chamber 42 loses volume, the chamber 38 can gain in volume, which can be prevented with appropriate dimensioning of the flow-influencing elements that too high a dynamic effects occurring pressure difference between the chambers 38 and 42, the movement affected the actuators. The elements 46 and 48 may be configured such that the distance to the free ends of the actuators 22b remains small and / or approximately constant independent of the deflection of the ends. For strain relief of the actuators 22a, as described above, bending spring elements 72a may be arranged.

Previously described embodiments may include further actuators which are arranged in emerging flow channels. The other actuators can not serve, for example, the direct generation of sound, as is the case, for example, with the electromechanical see converter 18 can be used, but be used for variable adjustment of the flow characteristics. Thus, for example, the attenuation, and thus the width of the resonance curve, can be adapted individually and flexibly for each chamber during operation of the component (MEMS converter).

In the initial estimate, the volume change per active area (AV / A) for a prior art membrane loudspeaker was estimated to be 3.75 pm. This may be re-estimated for a MEMS transducer as shown in FIGS. 8a-c, using dimensions useful for microtechnology technology, as discussed below, to obtain an estimate for an active area AV / A. For this, a value of 5 pm can be assumed for a width of the actuators (in the x-direction in FIG. 8a). The width of the post 84 may also have a value of 5 pm. For the distance of the actuators, which form the side walls of the chamber 38, (for example in the unexposed state in FIGS. 8a and 8b), 10 pm can be assumed. For a distance of the actuators which form the side walls of the chamber 42 (Figures 8a and 8b in the unexposed state) 100 pm can be assumed. A pianar filling factor F _p , which can indicate which portion of the active area is usable for the generation of a volume flow, can then result in F _p = 100 / (5 + 100 + 5 + 10) = 83%.

AV / A can be expressed as: AV / A = A x F _p h / A = F _P h

In the above expression, h may represent the height of the chamber (eg, the z-direction in Fig. 8a). Simplified, only the actuator height can be assumed for this purpose. A thickness of the spacer layers 34a and 34b may be neglected. Compared with the above 3.75 pm for the membrane loudspeakers, it becomes clear that an actuator height of only 3.75 m / F _p (ie 4.5 pm) is sufficient to provide the same volume flow per active area. With an actuator thickness h of about 50 μm, which can be produced in micromechanical technology without increased efforts, the value can already be more than a factor of 10 higher than that of the MEMS membrane loudspeaker. In embodiments according to the MEMS converter 80, which are embodied without rigid plates, parasitic oscillations can be much easier to control or reduce due to the significantly reduced number of mechanical elements and mechanical connections than in variants which control the plate elements and optionally further. re deformable elements between the deformable element and the plate member have. A serial series connection of actuators, as shown for example in FIGS. 7b and 7c, can serve to achieve larger strokes or larger forces. 9 shows a schematic perspective view of a stack 90. The stack 90 comprises a MEMS converter 80a, which is connected to further MEMS converters 80b and 80c to the stack 90 and arranged in the stack 90. The electromechanical transducers of the MEMS converter 80a and of another MEMS converter 80b and / or 80c may be controllable together. This means that, with the chip area remaining the same, a volumetric flow that can be generated or recorded is increased. Although the stack 90 is described as comprising the MEMS transducers 80a, 80b, and 80c, alternatively or additionally, other MEMS transducers 10, 20, and / or 50 may be arranged. Although the stack 90 is described as including three MEMS transducers, the stack 90 may also include a different number of MEMS transducers, such as two, four, five, six, or more MEMS transducers. The cavities or partial cavities of the MEMS transducers or adjacent MEMS transducers, which are arranged in the stack 90, can be connected to one another. The cavities or partial cavities can be connected, for example, by openings in layers between individual MEMS transducers. The electronic circuit 17 may be configured to drive one or more of the MEMS transducers, ie, to provide the conversion between deformation of the deformable element and an electrical signal. The stack 90 can thus have at least one but also a plurality of electronic circuits 17.

In other words, based on silicon technology, chips or MEMS converters can be stacked, for example, by bonding methods, so that in this case, in contrast to the classical membrane loudspeakers, a further increase in the volume flow can result. When using technologies for thinning the individual slices or chips before stacking, the stack height can be kept low. Such a technology may include, for example, an etching process and / or a grinding process.

A reduction of a layer thickness of the layers 32a and / or 32b, which are arranged adjacent to one another, can be guided so far that one or even both of these layers are removed. Alternatively or additionally, to reduce the stack height, a production process may be carried out such that certain lower or upper covers (layers 32a or 32b) are omitted. For example, the Stack 90 may be formed so that the ME S converter 80b and / or 80c are each carried out without layer 32b.

10 shows a schematic perspective view of a detail of a MEMS converter 100 in which deformable elements 22a-d are arranged between sides of the substrate 14. The deformable elements 22a and 22b are indirectly connected via the anchor element 84a. This means that ends of the deformable elements 22a and 22b can be fixedly connected to the substrate, possibly with the anchor element 84a, and thus (fixed) clamped. This means that the deformable elements 22a-d or other deformable elements according to further embodiments may have a beam structure. The beam structure may be firmly clamped at first and second ends. A clamping of ends of a deformable element 22a-d or a beam structure makes it possible to reduce or significantly reduce a deflection of the deformable elements (for instance due to layer stress gradients). Thus, the gaps between the covers and the actuators can be much smaller, which has considerable efficiency advantages for some applications

The deformable elements 22a-d are, for example, firmly clamped on both sides. A fixed clamping can be obtained by means of an arrangement or production of the deformable elements 22a and / or 22b on the substrate 14 and / or on an anchor element 84a or 84b. Dashed lines 88 indicate an undeflected state, whereas solid bars 92 indicate a deflected shape of the deformable elements 22a-d. Formations or elements 94a and 94b of the substrate 14 may enable positioning of the deformable elements 22a-d along the y-direction. A paired position of electromechanical transducers 18a-c may be shifted based on elements 94a and 94b. Adjacent and / or in pairs mutually arranged electromechanical transducers 18a and 18b may be mutually deformable opposite to each other. The deformable element 22a and possibly an opposing deformable element 22c may be designed to influence, ie to enlarge or reduce, based on the deformation, a partial cavity section 96a or to perform a deformation based on the volume flow in the partial cavity section 96a. The deformable element 22b and optionally the oppositely disposed deformable element 22d may be formed to affect a Teilkavitätsabschnitt 96b. The Teilkavitätsabschnitte 96a and 96b may be interconnected, such as in a portion of the anchors 84a and 84b. The deformation of the deformable elements 22a-d can be obtained so that the deformable elements 22a and 22c or 22b and 22d deform with a mutually different frequency, ie a volume change in the Teilkavitätsabschnitt 96a can be made with a frequency that is of a frequency is different, with which a volume of the Teilkavitätsabschnitts 96b changes. If the MEMS converter is used, for example, as a loudspeaker, different frequencies can be obtained in the partial cavity sections based on the frequency-wise different volume change. For example, when the MEMS converter 100 is used as a microphone, the partial cavity portions 96a and 96b may have mutually different resonance frequencies. Alternatively, further Teilkavitätsabschnitte and other deformable elements along the y-direction may be arranged so that the MEMS converter 100, for example, generate further frequencies or may have other resonant frequencies. Alternatively, the deformable elements 22a and 22b or the deformable elements 22c and 22d may also be directly connected to each other. For example, anchor elements may be disposed in a central region of one or more deformable elements 22a-d to affect the deformation of the deformable elements 22a-d. This means that the deformable elements 22a and 22b can be directly connected to each other. Alternatively, a spring element or another element may be arranged between the deformable elements 22a and 22b.

The MEMS converter 100 may be designed in such a way that, in a first time interval, the volume flow 12 is obtained in a positive y direction from openings 26 and subsequently, in a second time interval, the volume flow 12 is obtained in a negative y direction from openings 26.

In other words, FIG. 10 shows a configuration in which, in turn, exclusively, S-shaped actuators are arranged. To illustrate the principle, the S-shaped actuators can be represented in the illustration both actuated (solid lines 92) and non-actuated (dashed lines 88). Actuated and non-actuated state can also be interchangeable by appropriate design. The S-shaped actuators (deformable elements 22a-d) can be clamped both at their one (upper) and at the other (lower) end. For this purpose, the anchor elements 84a-b can be used. The anchor elements 84a-b may be formed from the layers 34a, 36 and 34b and connected to a layer 32a and / or 32b. Distances between the Free ends of the S-shaped actuators and elements 94a or 94b may be omitted based on this configuration. This can allow lower flow losses. A starting substrate can be processed in such a way that the actuators can be produced therefrom, wherein the starting substrate can have layer stress gradients, or layer stress gradients can be introduced during the production of the actuators. A deflection of the deformable elements induced thereby can be reduced or prevented based on the arrangement of the anchor elements 84a and / or 84b. In particular, the bilateral suspension of the deformable members may result in reducing or preventing deflection thereof toward one of the layers 32a or 32b. The spacer layers 34a and 34b can accordingly be thinner, which in turn can bring about a reduction in the flow-through losses. Each chamber (Teilkavitätsabschnitt 96a or 96b) may be limited by two S-shaped actuators. In the example of FIG. 10, two chambers may be serially connected in series. The number of serially connected chambers may be selectable based on an area provided on the chip taking into account the acoustic properties, in particular the resonance frequency of the S-shaped actuators or the actuator chamber system and may be between 1 and a high number, for example more as 3, more than 5 or more than 10 vary. The elements 94a and 94b can optionally be arranged, ie the ME S converter 100 can also be designed without these elements. If, for example, a corresponding part of the actuator is not deflected due to a special design or control of the electromechanical transducers and / or the deformable elements, it is possible to dispense with a spacing from the substrate 14 by means of the elements 94a or 94b. A multiple S-actor (wavy actuator) can be made, in particular, this enables obtaining low resonance frequencies based on this arrangement, since a resonant frequency of the beam (deformable element) may decrease with increasing length. 1 a shows a schematic plan view of a section of a ME S transducer 1 10, in which the electromechanical transducers 18 a - b are compared with the configuration of FIG. 10 with respect to a lateral direction of the substrate 14, for example the x direction. are arranged obliquely. In a comparison with the MEMS transducer 100 same extent along the y-direction, the electromechanical transducers 18a-b may have a longer axial extent. This can be larger partial cavity sections 96a and / or 96b and / or allow a higher number of serially connected in succession Teilkavitätsabschnitte or deformable elements.

An outer beam segment 30a of a deformable element may be indirectly connected via the anchor element 84 to an outer beam segment 30c of another deformable element. Alternatively, the beam segments 30a and 30c may also be directly, i. h., be directly connected with each other.

In other words, FIG. 11a shows a further exemplary embodiment in which the active surface is rotated by 45 ° compared to the embodiments of FIG. 10, wherein the available chip area may possibly be utilized to a greater extent. Funnel-shaped openings 26 may be configured such that the sound is preferably perpendicular to the chip edge surface, i. H. along the y-direction in the positive or negative direction thereof can be emitted.

Each of the above-described deformable elements may also be formed as a plurality of deformable elements interconnected with each other.

1 1 b shows a schematic plan view of a section of a MEMS converter 1 10 ', which can be used, for example, as a pump. Compared with the MEMS converter 110 of FIG. 11a, the partial cavity sections 96a and 96b can be connected to an environment of the MEMS converter 1 10 'via two openings 26a and 26b. The Teilkavitätsabschnitte 96a and 96b may be connected via the opening 26a to a first side 97a of the MEMS converter 1 10 'and be connected via the opening 26b with a second side 97a of the MEMS converter 1 10'. The first side 97a and the second side 97b may, for example, be arranged opposite one another. Alternatively, the sides 97a and 97b may also be at an angle to each other. For example. For example, one of the sides 97a or 97b may include one side surface of the MEMS transducer 110 ^' and the other side 97b or 97a may include a main side (eg, top or bottom) of the MEMS transducer 110'.

Based on deformation of the deformable elements 22a-d, fluid flow may be generated from the first side 97a to the second side 97b or vice versa through the MEMS transducer 110 '. For example. For example, the deformable elements 22a and 22c can be deformed in a first time interval and the volume of the partial cavity section 96a can be reduced. In a second time interval, the volume of the partial cavity section 96b be reduced. Based on an order of decreasing or increasing the volumes, a direction of the volumetric flow 12 can be influenced. Alternatively, several Teilkavitätsabschnitte can be arranged one behind the other or only a Teilkavitätsabschnitt be arranged.

In simple terms, the function of a pump can be obtained by the volume flow 12 is generated instead of back and forth analogous to a loudspeaker according to a flow principle by the MEMS converter. An inlet and an outlet side of the ME S transducer may be arranged opposite one another, but may alternatively also have an angle to one another or be spatially or fluidly spaced from one another on the same side. The cavity comprising the partial cavity portions 96a and 96b may include the openings 26a and 26b in the substrate. At least one of the electromechanical transducers 18a or 18b may be configured to provide the volumetric flow 12 based on the fluid. For example. For example, at least one of the electromechanical transducers 18a or 18b may be configured to propel the fluid in a direction of the cavity based on actuation of the electro-mechanical transducer through the first opening 26a or into a fluid based on the actuation through the second opening 26b Direction away from the cavity or vice versa.

Although a pump function in connection with the MEMS transducer 1 10 'is described, other embodiments described here can be used as a pump or micropump, such as by an arrangement of openings of the cavity, Teilkavität or at least a Teilkavitätsabschnitts is adjusted.

With a simultaneous deflection of the deformable elements 22a and 22e, a negative pressure (alternatively overpressure) can result in an intermediate volume, which counteracts the deformation or deflection. The volume may have an opening, for example in the layer 32a and / or 32b, so that a pressure equalization in this volume is made possible. This enables efficient operation of the MEMS converter 110 '.

FIG. 12 a shows a schematic view of a MEMS converter 120 which, for example, can be used as a MEMS pump, in a first state. The MEMS converter 120 has, for example, two deformable elements 22a and 22b, which have a beam structure and are clamped on both sides of the substrate 14 or firmly clamped. alternative For example, the MEMS converter 120 can also be designed with a deformable element or with more than two deformable elements.

FIG. 12b shows the MEMS converter 120 in a second state. Based on a deformation of at least one deformable element 22a and / or 22b, the second state can be obtained starting from the first state, as shown in FIG. 12a. Starting from the second state, the first state can be obtained based on a rebound of the deformable element or elements. In the second state, the partial cavity 38 between the deformable elements 22a and 22b is enlarged, for example, with respect to the first state. During a transition from the first to the second state, a negative pressure in the Teiikavität 38 arise. During a transition from the second state to the first state, a negative pressure in the Teiikavität 38 arise. Between a deformable element 22a or 22b and the substrate 14, a Teiikavität 42a and 42b is arranged, the volumes of which can be reduced or enlarged complementary to the volume of Teiikavität 38, also complementary to Teiikavität 38 based on an overpressure or negative pressure can be obtained on the deformation of the deformable elements.

In a region of a respective opening 26, a valve structure 85a-f may be arranged. For example, one or more valve structures 85a-f may be formed of a material of the substrate 14. The valve structures may be formed integrally with one or more layers of the substrate 14 and, for example, be produced by means of an etching process.

The valve structures may be configured to obstruct, ie, reduce or prevent flow of the volume flow 12 through the opening 26 at least along one direction. For example. For example, the valve structures 85b, 85d, and 85f may be configured to reduce or prevent leakage of the fluid from the respective partial cavity. Alternatively or additionally, the valve structures 85a, 85c and 85e may be formed to reduce or prevent ingress of the fluid into the respective partial cavity. One or more valve structures 85a-f may be passively formed, such as a cantilevered cantilever structure or tongue structure. Alternatively or additionally, one or more valve structures 85a-f may be actively formed, such as an electro-mechanical transducer or deformable element. Put simply, For example, the valve structures 85a-f can be actuated like the other actuators (electromechanical converter) of the MEMS converter.

The valve structure 85d may, for example, be designed to allow the volume flow 12 to flow into the subcavity 38 based on a negative pressure in the subcavity 38, while the valve structure 85c simultaneously reduces or prevents the volume flow 12 from entering the subcavity 38. Occurs, as shown in Fig. 12b, an overpressure in the Teilkavitat 38, the valve structure 85 c may be formed to flow based on the excess pressure, the flow rate 12 from the Teilkavitat 38, while the valve structure 85 d at the same time a discharge of the volume flow 12 reduced or prevented from the Teilkavitat 38.

A function of the valve structures 85a, 85b or 85e and 85f may be the same or comparable with respect to the partial cavities 42a and 42b. The valve structures 85a-f may also be referred to as check valves and allow, for example, a setting of a preferred direction of the volume flow 12th

Although the MEMS transducer is described as having, for example, the volumetric flow from the subcavities 38, 42a and 42b along the same direction (positive y direction) and during different time intervals during which transition occurs between the first and second states, flows, the valve structures may also be arranged so that the volume flow from at least one Teilkavität 38, 42 a or 42 b flows along another direction, such as the negative y-direction. Although the MEMS transducer is described as having valve structures 85a-f disposed on each aperture 26, valve structures may alternatively be disposed on none or only a few apertures 26.

Although the valve structures may be passive for a function as a check valve, the valve structures may also be actively formed, that is, they may be controllable and provide an open or closed state of the valve in the sense of actuators based on the drive. In particular, two valve structures 85a and 85b, 85c and 85d or 85e and 85f, which are each assigned to a partial cavity, can be controlled such that pressure pulses are generated in the fluid flow 12, for instance by a control device connected to the MEMS converter. For example. An actuation of the electromechanical transducers 18 can take place in such a way that a Over- or underpressure is built up in the fluid within the partial cavities 42a, 42b and only then an opening of the valve structures 85a-f is activated.

In other words, with such pressure pulses an approximate reproduction of a low-frequency sound wave by short pressure pulses can be achieved. By a plurality of chambers arranged serially one behind the other, this can be done in a nearly continuous manner. Similarly, this is possible with parallel adjacent chambers. Fig. 12a shows an example in the non-actuated state, in which each chamber is provided at the top and bottom with a respective valve, which can be actively formed. Each valve can be opened or closed individually. Even a partial opening / closing is conceivable. The valve beams can be designed and operated in the same way as the movable side walls, i. h., the deformable elements. They can therefore be based on the same or the same actuator principle. In this case, these valve bending beams can also be designed so that they are movable in both directions, or the opening (by appropriate applied by the bending actuator valve counterforce) in fluid flow, close (except for a very small gap required for the movement With this design, there is full flexibility to control the fluid flow in terms of direction, under / over pressure, individually for each chamber, and if the fluid flow direction is fixed, valve stem stops can also be used ("Check valve").

In still other words, in the first state, the middle chamber (partial cavity 38) can be expanded by the two dark actuators (deformable elements 22a and 22b), while the two outer chambers (partial cavities 42a and 42b) are compressed. The first chamber fills via the check valve 85d with the fluid from the lower region. The latter push fluid into the upper area through the check valve 85a or 85e. In the second state, the middle chamber is compressed. Fluid is pushed into the upper area. The outer chambers fill with the fluid from the lower area.

13 shows a schematic view of a first deformable element 22a and a second deformable element 22b, which are connected to one another along a lateral extension direction 98 of the deformable element 22a and / or 22b. Between the deformable element 22a and the deformable element 22b, a spring element 102 is arranged. The spring element 102 can cause reduced mechanically induced restoring forces in the deformable elements 22a and 22b. For example For example, the spring element 102 may have a low rigidity in a direction 98 ', which is perpendicular to the direction 98, and a high rigidity along a direction 98 ", which may be arranged perpendicular to the direction 98 and 98' deformable elements 22a and 22b and the spring element 102 can be arranged, for example, as the deformable element 22a in the MEMS converter 110.

In other words, suitable spring elements 102 can be arranged for strain relief of the S-shaped actuators 22a-d clamped on both sides at clamping locations or, for example, also in a region between clamping locations, approximately in the center. The spring element 102 is, for example, inserted in the middle of the actuators and is particularly flexible in the desired direction (98 ') and rigid in the two directions (98 and 98 "), ie it has a high or high rigidity The spring element 102 may have a lower stiffness along the lateral movement direction 24 than in a direction perpendicular to the lateral movement direction 24.

14 shows a schematic view of a stack 140 comprising a MEMS converter 80'a and a MEMS converter 80'b, which are connected to one another and, in comparison with the MEMS converter 80, have a common layer 32, which means a layer 32a or 32b of the MEMS converter 80 is removed. The electronic circuit 17 may be configured to jointly drive the MEMS converters 80'a and 80'b. Alternatively, each of the MEMS converters 80'a and 80'b may have an associated electronic circuit.

Furthermore, the MEMS converter 80'a in the layer 32b, the openings 26, which means, compared to the MEMS converter 80, a radiation direction of the volume flow 12 and a direction of penetration of the volume flow 12 is tilted vertically. This means that a cover surface of the MEMS converter can form an outer side of the stack, wherein the MEMS converter can have an opening in the cover surface, which is arranged facing away from a side facing the second MEMS converter, wherein the volume flow 12 of the MEMS transducer 80 'a perpendicular or opposite to the flow of the MEMS converter 80' b from or enters the cavity. A membrane element 104 can be arranged on the MEMS converter 80 ^' a. The membrane element 104 may be arranged so that an outlet of the volume flow 12th from the cavity and through the membrane element 104 or an entrance of the volume flow 12 into the cavity 16 is at least partially prevented. The cavity may extend to regions disposed outside of the MEMS transducer 80'a and disposed between the MEMS transducer 80'a and the membrane element 104. Based on the volume flow 12, a deflection of the membrane element 104 can be effected. The membrane element 104 can be arranged, for example, by means of a frame structure 106 on the MEMS converter 80 'a. The frame structure 106 may be disposed on a side of the MEMS converter 80'a, such as on a major side of the layer 32b.

Alternatively, a tilt can be performed by an angle different from 90 °. The MEMS converter 80 'b may have openings on or in the layer 32 b so that the volume flow 12 can enter and exit cavities on two sides of the stack 140 and / or out of cavities, the sides being arranged opposite to one another are.

Alternatively or additionally, the stack 140 may also comprise a further or different MEMS converter, for example the MEMS converter 20 or 80. For example, the MEMS converter 20 may be arranged between the MEMS converters 80'a and 80'b. This allows entry or exit of the volumetric flow 12 into or out of cavities along a direction that is perpendicular to a corresponding direction of the MEMS transducer 80'a.

In other words, sound exit openings 26 may also be mounted in the lower lid 32a and / or in the upper lid 32b instead of on the chip side surfaces. Fig. 14 shows a corresponding simplified representation. The openings 26 in the upper lid 32b can be seen. Similar openings may be in the lower lid 32b, but are not recognizable based on the perspective view. The layer 32 may also have openings, that is, cavities, partial cavities and / or partial cavity portions of the MEMS transducers 80'a and 80'b may be interconnected. Via the openings in the layer 32 may be vertically interconnected (along the z-direction) superimposed chambers.

A grid comprising one or more rod elements (grid bars) 44, which can be designed to set the damping and in particular as protection against particles, can also be easily realized in the variant described in FIG. 14. For example For example, the openings 26 in the upper lid 32b and the lower lid 32a may be formed by a wet or dry chemical etching process. Before the etching, the desired lattice can be patterned in an additionally applied thin layer, which has a suitably high selectivity for the etching of the openings. For the etching of the openings 26, an etching process with a suitable high isotropy or lateral undercutting can now be selected so that the grid webs 44 can be undercut. By way of example, the lattice can be produced in a silicon oxide or nitride layer and the lids can be made of silicon, which can then be structured by means of deep reactive ion etching (DRIE). This process can be set to achieve undercuts on the order of microns. Alternatively, for example, a wet-chemical etching with tetramethylammonium hydroxide (TMAH) and / or potassium hydroxide (KOH) or nitric acid (nitric acid - HNA) can be carried out. With appropriate funnel-shaped design of the openings in the lower ceiling! 32a and in the upper lid 32b, the sound exit surface may thus comprise a larger portion of the chip area and be made larger, if necessary, as compared to MEMS converters having an exit on a side surface, such as the MEMS converter 80. This option offers further freedom in terms of acoustic properties and damping. A combination of sound exit openings in the covers 32a and 32b and the side surfaces between the cover surfaces 32a and 32b is a feature of further embodiments. A preferred variant for highly integrated systems may include the provision of openings in the lid 32b to deliver the sound upwards and include the attachment of the pressure equalization openings on the side in order to be able to easily apply the component to a printed circuit board, for example.

In general, the sound inlet openings or sound outlet openings 26 can be designed such that the acoustic properties and / or the damping properties are set in a targeted manner. The lower and / or upper layers 32a and 32b may in principle also be capable of oscillation. The oscillation of these elements can be suppressed or reduced by suitable additional connecting elements in the intermediate layers 34a and 34b or 36, for example by the armature elements 84. The suppression or reduction can include shifting the oscillation into a frequency range outside of the sound of hearing lies. Alternatively or additionally, the oscillation of the layers 32a and / or 32b can also be targeted for optimization be implemented the acoustic radiation, whereby also targeted compounds can be used in the layers and additionally the stiffness or the acoustic properties of the layers 32a and 32b by appropriate structuring (through holes or blind holes) can be adjustable.

In addition, it is possible to apply a membrane to the upper lid 32b, which is then excited by the volume flow 12 of the chambers to vibrate. This is indicated schematically by the dashed line 04. In a simple case, a spacer in the form of a frame or spacer (spacer) 106 may be arranged on the upper cover 32b, on which the membrane 104 may be arranged or clamped. The production of such a membrane 104 can take place with known micromechanical processes. Alternatively, the membrane 104 can also be arranged in the interior of the cavity or partial cavity and / or cover only one or a portion of the openings 26.

For some of the above-described embodiments of MEMS converters (such as MEMS loudspeaker components), it can be said that there are chambers which can generate a partial volume flow independent of some, several or all other chambers, for example in partial cavities or partial cavity sections. Chambers can be realized which consist of subchambers which are contiguous in the lateral and / or vertical direction (laterally see, for example, FIGS. 10 and 11) (vertically see, for example, FIG. 14), wherein exemplary embodiments also show a combination thereof. Such contiguous subchambers (such as subcavity sections 94a and 94b) may be utilized to create a subvolume stream independent or dependent on other chambers or subchambers. A case in which a chamber (partial cavity) can generate a volume flow independently of one another can be referred to as a mono-chamber. A chamber that can generate a volume flow based on a plurality of subchambers (subcavity sections) may be referred to as a composite chamber.

Previously described embodiments are modifiable so that both types of chambers are arbitrarily combinable. Thus, embodiments are possible in which only mono-chambers or exclusively composite combs are arranged. Alternatively, embodiments can be realized in which both chamber types are arranged. in other words, when using only mono-chambers, the resonance frequencies of all actuator / chamber systems can be identical or can be designed differently. Thus, for example, certain frequency ranges in the sound radiation can be highlighted by an increased number of corresponding mono-chambers. In particular, by appropriate distribution of the resonance frequencies and the width of the resonance curves via the damping z. B. by the dimensioning of the grid openings or generally the sound outlet openings or the flow channels, a design of the frequency response (sound pressure level as a function of frequency) can be achieved. Above all, the smoothing of the frequency response plays an essential role.

Partial cavities and / or partial cavity sections can be based on spatial expansions of the volumes, a geometry of the electromechanical transducers and / or a frequency with which the electromechanical transducers are operated to emit the volume flow at a different frequency and / or be optimized for the detection of certain frequencies of the volume flow.

In a further embodiment, only mono-chambers are used. The sound outlet openings can be arranged only laterally. Three chips / disks (MEMS converters) can be stacked on top of each other. The upper chip may be optimized for sound radiation in a first (eg high frequency range). A second, approximately middle, MEMS converter may be adapted to a second frequency range (approximately medium frequencies). A third MEMS converter may be adapted for a third frequency range, such as low frequencies. This can be a three-way speaker can be obtained. The arrangement of the three channels (three MEMS converters) could also be done in one chip by adding laterally a first number N, of chambers for the high frequencies, a second number N ₂ of chambers for middle frequencies and a third number N ₃ for low frequencies Frequencies is used. This principle can easily be extended for an N-way system in lateral and stacking, even in the vertical direction. In another embodiment, an N-path system is configured to generate the sound via Fourier synthesis of the respective harmonics having the frequencies N ^* f, where f, represents the lowest frequency.

This means that a MEMS converter with at least one further MEMS converter can be arranged in a stack, wherein a stack, for example, by an arrangement of at least two MEMS transducers along a lateral direction (approximately the x-direction) and / or a thickness direction (about the z-direction) can be obtained. Alternatively, the MEMS transducers may also be spaced from each other. The cavity of the MEMS converter and the cavity of the at least one further (second) MEMS converter may have a resonance frequency which differs from one another.

In an actuator operation, i. that is, the deformable elements are actively deformed, an N-way loudspeaker can be obtained, where N denotes a number of MEMS transducers with mutually different resonance frequencies. In a sensor operation, for example, different frequency ranges of the volume flow can be detected with different MEMS transducers. This allows, for example, a Fourier synthesis of the volume flow. For example. For example, the controller 128 may be configured to detect the deformation of the deformable elements of one or more of the electromechanical transducers of the MEMS transducer and the another MEMS transducer. The control device may be configured to calculate a Fourier synthesis based on the electrical signals and output a result.

The examples just described using mono-chambers can also be realized when using composite chambers, wherein the individual sub-chambers of a composite chamber have identical resonance frequencies.

When using composite chambers, the contiguous sub-chambers can also support different frequencies by corresponding position of the resonance maxima. For example, three subchambers could represent a three way system. The z. For example, in the rear part chamber (first section along an axial extension) low-frequency modulated air flow would be additionally medium-frequency in the middle part chamber (second part along an axial extension) and in the front part of the chamber (third part along an axial extension) experience a high-frequency modulation. At high frequencies, not a required stroke, so a deflection of the electromechanical transducer to be lower than at low frequencies to produce the same sound pressure. The chambers or sub-chambers, which are used for high frequencies, can thus be designed with a smaller chamber volume or distance of the chamber bounding the actuator side walls. During operation, a phase offset can be introduced via the control between chambers of the same frequency, so that the wavefront is tilted and does not exit perpendicular to the surface (phased array). In all variants presented heretofore and in the following, each chamber is surrounded by at least one second chamber into which air flows in order to equalize the pressure when air flows into the first chamber or vice versa. Obviously, this is especially true when there are no partitions between these chambers, as an actuator increases the volume of one chamber while reducing the volume of the other chamber, and vice versa.

For use z. B. as speakers in hearing aids or in-ear headphones is often the outside air (ie the outside of the ear) is not moved through the speaker. Rather, only by the oscillation z. B. a membrane, the volume in the ear canal varies periodically. This can be done in all variants presented and in the following by the corresponding openings, which lie in the illustrated variants either on a chip top side, a chip bottom side or on a chip side surfaces remain closed. For this purpose, it is only at these points to dispense with the structuring of the bar grille.

Generei! applies and applies to all speaker areas, that bar grille can be replaced in certain places or completely by a closed membrane. Thus, the particle sensitivity is maximally reduced and enables the operation in particular in contaminating or corrosive gases and liquids.

In the following, measures in the design and operation of the bending actuators are presented, which have the goal to represent the desired frequency response as well as possible. By incorporating a plurality of additional spring elements, which divides the bending actuator into individual elements, the effective stiffness of the actuators and thus the resonance frequency can be reduced. For example, see Figure 15, where a single spring element was used to divide the bender into two elements. The division into two or more elements is important for achieving a resonant frequency in the low frequency range of the audible sound, since the bending actuators without such a measure in conventional dimensions of the bending actuators (eg., Width 5 μιτι, length 2 mm, Mate- rial silicon) have natural frequencies in the kHz range. Alternatively or additionally, an additional mass element can be deliberately provided on the bending reactor or also on the optionally present rigid plate in order to reduce the resonance frequency. Such an element can be provided in a simple manner in the structuring of the layer 36. The mode of action of an additional mass Am can be explained on a model of the harmonic oscillator.

The oscillation amplitude Α (ω) of an element of mass m suspended by a spring of stiffness k is given in sinusoidal excitation with a force of amplitude F ₀ as:

Here, ω is the angular frequency of the excitation and c the damping constant. If the resonator is operated in the quasi-static range, the amplitude is independent of the mass. It holds for ω «ω ₀ :

Α (ω) ~ F ₀ / k (gig 4)

Therefore an additional mass at the changes the natural frequency co ₀ (to the lower value> o, but the amplitude of oscillation remains unchanged. In contrast, the situation is is when the bending actuator is operated in the area of its natural frequency. For ω = co ₀ can the first term in the root of Gig. 3 is neglected against the second term and it holds:

Α (ω) ~ F ₀ / (c ( _0. ) (Gig. 5)

Since (o _{0) is} inversely proportional to the root of the mass of the oscillator, an increase in the mass causes a corresponding reduction of ω _0- and thus an increase in the amplitude.The gain in amplitude results under the condition c (Ü ₀ - < k) The possibility has already been described above for the bending beams to be constructed in such a way that they bend in one direction or the other, depending on the addressing or signal, so that the restoring force is no longer necessarily due to the mechanical spring effect when the beam is bent All the same less the stiffness of such a bending beam is selected, the greater the deflection is at a fixed einkoppelbarer energy.

While all considerations have related to the field of sound, it is conceivable that the component should also be designed for the generation of ultrasound. In principle, it is also conceivable that, instead of actuators, beams are provided with position-sensitive elements (eg, piezoresistive, piezoelectric, capacitive, etc.), in order then to provide a component as a microphone. For the core of manufacturing of silicon MEMS speakers, known wafer bonding techniques and deep reactive ion etching can be used. The production of the actuators depends on the chosen operating principle and is initially hidden. This part can be incorporated modularly into the following exemplary process. The following diagram refers to a component with only lateral borrowings for the air flow.

As starting material, BSOi (bonded silicon on insulator, bonded silicon on an insulator) disks are used. The handle wafer forms the lower lid 32a of the MEMS loudspeaker device. The buried oxide layer of the BSOi disk may later act as a spacer layer 34a. The active layer of the BSOI disc may correspond to layer 36. The carrier disk may have a thickness of 500 to 700 .mu.m and may be further thinned if necessary - possibly at the end of the process. The buried oxide layer may have a thickness of 50 nm to 1 pm. The active layer of the BSOI disc may have a thickness of 1 to 300 μm. The layer 36 is, for example, preferably structured with deep reactive ion etching (DRIE). After this structuring, the buried oxide layer (34a) can be removed or at least thinned at least locally in the movement region of the actuators. This can be wet-chemically, z. B. with BOE (Buffered Oxide Etch - buffered HF solution) or dry chemical, z. B. by means of gaseous HF (hydrofluoric acid), take place. After at least partial removal of the spacer layer 34a in the range of motion of the actuators z. Example, via a vapor deposition (chemical vapor deposition, chemical vapor deposition - CVD or atomic layer deposition, atomic layer deposition - ALD) are deposited a low-friction layer, which closes the gap between the layer 34a and the actuators (deformable elements) or greatly reduced. Alternatively, areas can already be defined during the bonding of the panes for the production of the BSOI panes by deposition and structuring of suitable layers in which no bonding takes place, as described, for example, in US Pat. No. 7,803,281 B2. Such a method can be used for upper and lower covers. The layer 34b is preferably structured, for example, by means of reactive ion etching (RIE). With these two structures, all elements in layer 36 and 34b are made as shown in the corresponding figures. This also includes the rod-shaped lattice structure.

The above-described deposition of a low-friction layer can also be used for the upper lid (layer 32b). This is then z. B. applied to the lid before bonding. The spacer layer 34b can then be dispensed with. For example. For example, a low-friction layer can be obtained by depositing a material. For example, a coefficient of friction may be 10%, 20%, or 50% less than a material of layers 32a, 34a, 34b, or 32b. The layer 36 can also be used as an electrical conductor with appropriate doping. Especially when actuators with different frequencies are to be excited, a vertical electrical insulation in layer 36 is advantageous. This can be z. B. by so-called filled trenches, as described in [8] can be achieved. The use of open trenches for electrical insulation is also an option.

A layer is applied and patterned onto a second wafer, which may be formed as a silicon wafer having a typical or possible thickness of 500 to 700 microns, and will, for example, form the top lid 32b. This layer corresponds to the spacer layer 34b. The thickness of this layer preferably corresponds to that of the buried oxide layer. As the material for the spacer layer, all materials are available which allows the later to be performed bonding of the second disc on the BSOI disc. Exemplary here is called silicon oxide, preferably thermal oxide for the direct bonding of silicon oxide on silicon. Alternatively, polysilicon can also be used for the direct bonding. A further alternative is to etch recesses which are suitable for the second disc, so that the function of both the upper cover 32b and the function of the spacer layer 34b is reproduced from the disc. These depressions can be dispensed with, at least in the area of the actuator movement, if the pane is coated with a suitably low-friction layer at these locations, so that the distance between actuator (movable element) and lid (layers 32a and / or 32b) can be dispensed with , On another layer on the second pane - apart from auxiliary layers (masking) for structuring - can be waived then. This also allows the direct bonding of silicon on silicon.

In addition to direct bonding, it is also possible to use an adhesive bonding process so that the spacer layer 34b then consists of a polymeric material (eg BGB). Conceivable, for reasons of non-existent CMOS compatibility but not preferred, are also Au-Si eutectic bonding method or anodic bonding method (Na-ion containing layers). After bonding of the two discs, the core of the production in the laminated composite is completed. The production of electrical wiring and contacts and possibly required electrical insulation structures was not carried out. These elements can be provided by known standard processes according to the state of the art: production of interconnects z. Example by sputtering and structuring of AlSiCu, vertical isolation by deposition and patterning of oxides, lateral isolation by open or filled isolation trenches, which completely penetrate the layer 36.

The separation of the components with side-mounted openings requires in particular the protection of the bar grids. This is z. B. allows by the device within a frame with this z. B. is connected via four thin webs. For this purpose, lower lid 32a and upper lid 32b, as well as the layers 34a, 36 and 36b to be structured accordingly. For this structuring are mainly anisotropic etching, such. As TMAH, KOH and DRIE in question. Especially for the structuring along the bar grids, the DRIE structuring of the layer 36 is the preferred variant. To dislodge the components of the disc composite, the webs are destroyed. This can be z. B. done mechanically or by laser processing.

It is also conceivable not to structure the lower lid 32a for the singulation, but only the layers 34a, 36, 34b and 32b. In particular, the layer 36 can be structured by means of DRIE in order to realize the vertical course of the bar grids. From the chip surface then results in a trench, which ends on the lower lid 32b. This trench can now be filled with a polymeric material (eg photoresist). The polymer serves to protect against contamination in the subsequent saw-singling process. After sawing, the components are rinsed and cleaned, to remove the sawdust. Subsequently, the polymer is removed by suitable solvents or in an oxygen plasma.

If openings in the lower and upper cover are used instead of the lateral openings, then the production is to be expanded, as already described in the context of FIG. 16. For the separation lower and upper opening z. B. be protected by a film so that sawing or laser cutting are possible. Alternatively, the openings may also be closed by a polymeric material, e.g. B. photoresist, are sealed for the separation process and then be removed by a solvent or in the oxygen plasma again.

The stacking of components is preferably carried out in the disk composite by bonding method. The electrical contacting can then take place either by electrical contacts (bond pads) in the respective layer 36 or, when using TSVs (through-silicon vias), also via so-called bumps on the chip underside. TSVs can also be used to electrically connect the stacked dies. For non-stacked chips TSVs and bumps can also be used.

In order to achieve a higher stability of the bar grids 54, the spacer layers 34a and 34b can remain unstructured in the region of the bar grids.

In the following, preferred embodiment variants for the production of the lateral bending actuators are described. In principle, known electrostatic, piezoelectric, thermomechanical and electrodynamic principles of action for the actuation of the bending beam can be used.

A simple electrostatic action principle can be realized for a part of the component variants shown above without active bending beam. The MEMS converter 50 may be designed so that rigid plate elements 62a and 62b are designed as capacitor plates or capacitor plates that move so far toward each other due to an electrical potential difference until the then acting as a bending spring elements 64 a corresponding mechanical counterforce exhibit. Alternatively, the bending bales can be deflected directly via an additionally arranged, fixed counterelectrode. The use of comb electrodes to increase the forces or the deflection is conceivable. Another electrostatic principle is based on the use of a cantilevered beam, which has a very small distance to an electrode at its clamping and this electrode spacing increases with increasing distance from the clamping. The distance at the clamping can be zero. If there is an electrical voltage between the bending beam and the electrode, then a part of the bending beam determined by the height of the electrical voltage and the rigidity of the beam will conform to the electrode. The space between the beam and the electrode, based on the principle described here, forms the chamber 42a, which can be changed in its volume as described. A basic principle of such actuators is described, for example, in the literature. In [9], for example, vertically deflecting actuators are presented. The variation of the electrode spacing is realized by targeted introduction of layer stresses in the production of the bending beam. For the device described in the context of this application, actuators could easily be realized according to this principle by appropriate structuring of the layer 36. In addition to the structuring of the layer 36, which is required in any case, an insulating layer is to be applied between the electrode and the bending beam, which is easy to implement by known methods of microsystem technology. The introduction of a layer tension is not required because the bending beams already obtained by structuring the desired shape. In the manner described here, the actuators are laterally deflectable and thus used for the component principle described above.

In terms of integration and scalability for high volumes, the electrostatic working principle offers a large number of advantages. No external components, such as magnets or coils are required, and no contamination-critical materials are required for clean rooms and, in particular, CMOS-compatible cleanrooms. The hitherto pursued membrane approach, however, has some disadvantages. This includes that with a single oscillating membrane or plate the entire Hörschallbereich can be covered only insufficient. The approach of operating the membrane or membranes quasi-statically solves this problem, however, due to the lack of resonance increase at the expense of the deflection and thus at the expense of the achievable volume flow or the achievable sound level. The latter hang for a fixed volume, such. For example, for in-ear headphones together [1 1]:

SPL stands for "Sound Pressure Level", P ₀ is the normal pressure, AM is the volume change that can be achieved through the loudspeaker, P _ref is the reference pressure, which indicates a measure of the threshold of hearing, it is 20 Pa, V is ₀ In the case of in-ear headphones or hearing aids, the volume of the ear cavity is about 2 cm ³ .

With regard to MEMS loudspeakers, it is therefore desirable to achieve the highest possible volume flow per chip area or per volume of the entire loudspeaker. Electrodynamic transducers can, for example, achieve very high diaphragm deflections and thus a high volume flow. However, the volume of the overall structure is very large due to the required permanent magnets. For speakers in mobile phones, which offer less and less space in perspective in one dimension, this approach generally appears restrictive.

Piezoelectric bending actuators require the deposition of a piezoelectric layer on a substrate. This piezoelectric layer could, for example, correspond to the layer 58 from FIG. 3, which is then arranged laterally to, for example, silicon-comprising or consisting of layer 56. The production of such actuators is possible with surface micromechanical processes. Lateral thermomechanical actuators in the form of a cold and a warm arm, such. As described in [10], can be very easily integrated by the corresponding geometries are taken into account in the above-described DRIE structuring of the layer 36. Another variant for thermo-mechanical actuators is the use of bimorphs, which are heated by electric current. For the production of such a bimorph, for example, after structuring the layer 36, an oxide layer could be conformally deposited, so that all side walls are also coated. This oxide layer could then be removed everywhere except on the one side wall of the bending element by masking and etching processes. The use of an electrodynamic principle of action is easy to implement for the cantilever beams clamped on both sides. When current flows through the bars or through a separately applied conductor structure, the bars experience a force in a magnetic field, which leads to deflection. The direction of the current flow can be selected for the individual bars according to the desired direction of deflection. The optional production of the printed conductors takes place using standard processes of surface micromechanics. The additional topography in the case is to be considered in the choice of the thickness of the spacer layer 34b.

The preferred embodiment for the bending actuator is a lateral electrostatic actuator, which relies on the use of very small electrode spacings and thus can operate and operate at low voltages. Such lateral actuators are described, for example, in EP 2 264058 A1. This technology allows the production of all the above-described bending actuator and component variants and can be integrated in a simple manner modular in the above-described core part of the manufacturing process of the components.

In the following, reference is made to the flow-around losses during the movement of the side walls, that is to say the deformable elements. Assuming laminar flow, it can be shown in a simple model that the flow-through losses, such as volume flows from chamber 42a to chamber 38a in FIG. 2a in comparison to the useful volume flows, ie the volume flow, which flows outwards or from the outside penetrates inside, can be suitably kept low, when the spacer layers 34a and 34b compared to the thickness of the layer 36 are small. The same applies to the distance at the optionally free end of a bending beam to the laterally delimiting structure. The latter can be omitted in both sides clamped bending actuators. If the flow losses are calculated for this configuration in the model of a laminar flow through rectangular tubes, then a loss due to the useful volume flow may result by circulations of about 3%, if the following is assumed for the dimensions:

Bending reactor: length 1 mm, height: 30 μm, width 10 μm Chamber: For the calculation of the flow resistance to the outside, a mean width of 50 pm was assumed. This underestimates the flow resistance with large deflection of the bending actuators. Layer thicknesses of the spacers 34a and 34b: 0.5 pm each

The assumed dimensions are only to be understood as examples and can be implemented very well with micromechanical technologies. The assumption of laminar flow could be incorrect due to the small width of the actuators (top: 10 pm), which corresponds to the tube length. However, this assumption is a worst-case assumption, since the turbidity increases the flow resistance. To motivate such turbulence, the bending actuators in the layer 36 may be provided with suitable laterally formed elements. Arrangements which form vortices when flowing around are to be regarded as suitable. Alternatively or additionally, a deliberate roughening of the chamber-facing surface of the lid 32a and 32b can promote the formation of a turbulent flow.

15 shows a schematic side sectional view of a deformable element 150, which has a first layer 1 12 and a second layer 1 14, which are spaced apart and connected to each other via connecting elements 1 16, wherein the connecting elements 1 16a-c at an angle of 1 90 to the layer 1 14 and the layer 1 12 are arranged. For example, the layers 1 12 and 1 14 may have an electrode. Alternatively, in each case one electrode can be arranged on the layers 1 12 and / or 14. Based on application of an electric potential, a repulsive or attractive force can be generated between the layers 1 12 and 1 14. The attractive or repulsive force can lead to a deformation of the elements 16a-c, so that a deflectable from a clamped end 1 18 deflectable end 122 of the deformable element 144 along the lateral direction of movement 24 is deflectable. This means that the deformable element 150 can have a first layer 14 and a second layer 16, wherein 16 spacers 16a-c can be arranged between the first layer 14 and the second layer 16. The spacers 16a-c can be arranged in an inclination direction 124 obliquely to a course of the layers 1 12 and 1 14. An attractive force between the layers 1 12 and 1 4 may cause a deflection of the deformable element 150. The deformable element 150 may be planar or simply curved along the direction of inclination. Alternatively, the deformable element or the layers 1 12 and / or 1 14 also have at least two discontinuously juxtaposed sections, approximately following a sawtooth pattern.

16 shows a schematic plan view of a deformable element 160 which is arranged adjacent to an electrode 126. The deformable element 160 can have a further electrode 127 or the further electrode 127. Based on an applied electric potential between the electrode 126 and the further electrode 127 of the deformable element 160, an electrostatic or electrodynamic force F can be generated. Based on the electrostatic or electrodynamic force F, deformation of the deformable member 160 may be effected.

In one of the volumetric flow or electric potential, i. H. For example, with the force F, unaffected condition of the deformable member 160, a distance between the deformable member 160 and the electrode 126 may vary along the axial extension direction 98 of the deformable member. In a region where the mechanical transducer or deformable element 160 has a connection to the substrate 14, the distance may be minimal. This allows a high controllability of the deformation of the deformable element 160. Alternatively, the distance between the electrode 126 and the deformable element 160 along the extension direction 98 may be arbitrarily variable or constant.

Electromechanical transducers can be formed according to embodiments as electrostatic transducers, as piezoelectric transducers, as electromagnetic transducers, as electrodynamic transducers, as thermomechanical transducers or as magnetostrictive transducers.

Based on a producible force, deformation of the deformable element may be effected or deformation of the deformable element may be detectable.

With reference to the following figures, some advantageous embodiments of the electronic circuit will be explained. FIG. 17 a shows a schematic perspective view of a MEMS converter 170 according to an exemplary embodiment. For the sake of simplicity, the layer 36 also includes the layers 34a and 34b described, for example, in connection with FIG. 2a. The cavity of the MEMS converter 170 is connected via openings 26 to an external environment of the MEMS converter 170. The electronic circuit 17 may be designed in several parts, so that a first part 17a of the electronic circuit 17 is arranged on or in the layer 32b. A further part 17b of the electronic circuit 17 can be arranged in another layer, for example the layer 32a and / or 36. The MEMS converter 170 may have on or in the layer 32b vias 19, which serve as contact pins for the input and / or output of electrical signals to or from the electronic circuit 17, for example.

Fig. 17b shows another schematic view of the MEMS converter 170 with the side 32a in the foreground. A second part 17b of the electronic circuit 17 may be arranged on or in the layer 32a. The layer 32a may also have vias 19. Some of the vias may have the same functionality. The plated-through holes can be used, for example, for the through-hole through the entire layer stack, one, some or all but only for parts of the stack, for example up to the deformable elements. Thus, in one example, some of the vias 19 may be the contacts to the deformable elements of the transducer, and others of the vias 19 may be those connecting the electronic circuitry of the lid wafer to the electronic circuitry on the bottom wafer.

FIG. 17c shows a schematic perspective view of the MEMS converter 170 analogous to the view in FIG. 17a, the openings being configured such that grid webs 44 are arranged in order to at least make it more difficult for particles to enter. The arrangement of the electronic circuit 17 in layers of the MEMS converter, such as the MEMS converter 170, on the one hand allows to obtain a highly integrated structure, which allows a reduction or avoidance of external circuit structures, so that the overall device can be made small. Furthermore, the arrangement of the electronic circuit in a layer of the layer stack makes it possible to obtain short signal paths, which is advantageous both for the range of electromagnetic compatibility and for time aspects and performance aspects of the device. Although an arrangement of the electronic circuit is possible in only one of the layers 32a or 32b, a division of the electronic circuit and an arrangement of the same in or on both layers 32a and 32b can provide advantages in that adjacent electronic components through as short paths as possible the electronic circuit 17 are driven. A division of the electronic circuit 17 further allows the electronic circuits 17a and 17b to implement different or complementary functions and / or be implemented in complementary technologies, such as MEMS and CMOS. Although the electronic circuits 17a and 17b may be in electrical connection with each other and / or with the electromechanical transducer. The structure of the MEMS transducer 170 as a layered structure makes it possible to fabricate the individual layers separately from one another, for example in mutually different semiconductor fabrication processes. This enables implementation of different functions at least influenced by the semiconductor manufacturing process in different layers and thus in different electronic circuits, so that circuit patterns 17a and 17b obtained in a chip of the MEMS converter 170 based on different semiconductor manufacturing processes can be arranged. This can also be understood as meaning that a first electronic circuit 17a is arranged in a first cover layer of the layer stack and that a second electronic circuit 17b is arranged in a second cover layer of the layer stack of the substrate. Each of the two electronic circuits 17a and 17b is arranged along a direction perpendicular to the in-plane moving plane. The deformable element may be arranged at least temporarily between the first and the second electronic circuit 17a and 17b during a deformation thereof. Through plated-through holes and / or other circuit elements, the electronic circuit 17 or the layer in which it is arranged, at least electrically connected to an outer side of the MEMS converter or represent the outside of the MEMS converter. This allows a contactability of the MEMS converter with a line arrangement, such as on a circuit board.

In other words, embodiments enable obtaining an overall device comprising different functionalities integrated in the MEMS converter. These include z. As the integrated electronic control of a MEMS loudspeaker and the control / readout of an integrated acceleration sensor. A production of individual functional elements can be used or implemented in different manufacturing processes, which may not be combinable or difficult to combine during the production of a wafer. By dividing these functionalities into two layers, such as the upper and lower wafers 32a and 32b, the manufacturing processes can be selected with greater flexibility and combined at the level of functionality, ie, assembled in the MEMS converter 170. For example, the upper wafer (lid) may include electronic circuit elements for the low voltage range, ie, small electronic structures requiring little space and allowing high speed. For example, the lower wafer (bottom) may include high-voltage D / A conversion for operating a loudspeaker, ie, large, high-capacity transistor structures that are slow. Likewise, a corresponding advantage can be obtained for memory elements, light sources or additionally integrated MEMS sensors / actuators. The integration of complementary functionality can be divided arbitrarily.

In still other words, an integrated electronic circuit 17 or 17a and / or 17b can be realized in the layers 32a and / or 32b. This can be used, for example, to control the actuators for the generation of sound and to set the respective electrical voltage according to the desired sound pressure, as well as to realize the electrical excitation at the desired frequency. Also an optionally required conversion of a digital electrical input signal into an analog control signal is possible with the integrated circuit, for example in the form of a D / A converter or by pulse width modulation (PWM). In the case of the microphone function can be realized in this circuit, for example, the electrical Signai (pre) processing - while maintaining short signal paths - or an A / D conversion. For the electrical contacting of the integrated electronic circuit 17 with the actuators / sensors inside the chip, vias 19 are conceivable, which can be arranged in the layer 32a and / or 32b. These can penetrate the layer 34a or 34b, so that individual continuous electrical connections from the integrated circuit to the individual actuators (bars) can be implemented. For example, two electrical contacts may be provided for each bar. On one side of the stack, the plated-through holes 19 may be connected via integrated strip conductors to the electronic circuit 17, which is not shown in the figures. For example, in manufacturing, a silicon CMOS (CMOS = complementary metal oxide semiconductor) wafer is bonded to layer 34b. This disc forms chip-related, the layer 32b and closes the chambers (cavity) from above. The vias in the silicon CMOS wafer can already be made before bonding (case a). In this case, it may be necessary for the through-contacts of the layer 34b to be present even before the bonding. Alternatively, it is also possible (case b) that both vias are made only after bonding. Simplified shown this can be done after bonding at the appropriate locations with the aid of a masking etching to the electrically contacted points of the bars and the resulting blind hole with an electrically conductive material, such as a metal or doped Halbleitermate- material, filled again become. Optionally, the side walls of the blind hole can be covered with an electrically insulating layer before filling with the electrically conductive material, for example silicon oxide and / or silicon nitride.

Although FIGS. 17a to 17c are illustrated with the electronic circuit arranged in two layers surrounding the cavity 14, the electronic circuit may also be disposed only on one layer, such as a layer configured to have one Board or the like to be associated, that is, a soil layer. Alternatively or additionally, additional functional elements can be realized in at least one of these layers, wherein this layer can then have plated-through holes. As an alternative or in addition to the arrangements of plated-through holes by means of selective etching, it is also possible to provide through-plating through the entire layer stack, for example by means of so-called "TSV" (through-silicon via), so that functional structures on the bottom layer and the cover layer are electrically connected could be. It may be a manufacture of the spacer layer 34b on the back of the lid wafer, i. H. layer 32b, and these common layers are then bonded to the wafer. Alternatively or additionally, a spacer layer 34a can be produced on the layer 32a, and this laminate can be joined together with other layers by subsequent bonding. The respective layers produced together may be contacted with other components prior to bonding. In principle, however, plated-through holes in the layers 32a and 32b or layers 34a and 34b arranged thereon can be provided at any point in the process sequence.

Alternatively or additionally, it may also be provided that a MEMS converter, as described above, is arranged in the cavity, that the cavity of a relatively thick wafer is formed, so that can be dispensed with at least some of the steps for performing a wafer bake.

Fig. 18a shows a schematic perspective view of a MEMS converter 180, in which the layer 32b faces the viewer, as is the case for example in Fig. 17a.

Adjacent to the electronic circuit 17a, the layer 32b may comprise a functional element or MEMS structure 21, which may have one or more MEMS functions. For example, the MEMS structure 21 may include an inertial sensor, a magnetometer, a temperature and / or humidity sensor, a gas sensor, or a combination thereof. Alternatively or additionally, it can be any desired sensor, an arbitrary actuator, a wireless communication interface, a light source, a memory module, a processor and / or a navigation receiver. The electronic circuit 17a can be designed to control and / or evaluate the MEMS structure 21.

This means that the layer 32a in which the electronic circuit 17a is located is a functional element, i. H. the MEMS structure 21, may include. The functional element may be connected to the electronic circuit, wherein the electronic circuit 17a may be designed to control or evaluate the functional element.

Rotation of the MEMS transducer 180 about an axis 23 may result in a view as shown in FIG. 17b, where the circuit 17b disposed on the side 32a may, for example, be configured to evaluate the electromechanical transducers of the MEMS transducer 180 inside the cavity / or to control. Again, the electronic circuits 17a and 17b may have complementary functions. In other words, the bottom wafer may have an integrated electronic circuit 17b, which preferably performs complementary tasks to circuit 17a. That is, the MEMS converter 180 may be configured to be disposed on a circuit pattern or board such that the MEMS structure 21 is disposed away from that structure. FIG. 18b shows a schematic perspective view of a MEMS transducer 180 'that is modified from the MEMS transducer 180 such that an opening 26a is disposed in the layer 32b and is located, for example, within the MEMS block 21.

This can be done, for example, such that the electronic circuit 17a is both designed to drive the electromechanical transducers in the interior of the cavity and / or read out and designed to actuate and / or evaluate the MEMS structure 21.

The MEMS transducer 180 'may include another opening 26b in the substrate. For example, the opening 26b may be arranged such that the fluid stream 12 travels a long distance through the MEMS transducer 180. By way of example, the opening 26b may be arranged on one or in one of the MEMS structure 21 of the maximally removed side wall of the MEMS converter 180 '. The MEMS structure (functional element) 21 may be formed, for example, as a gas sensory functional element, which is arranged in the cover layer 32b. The gas sensing functional element 21 may be configured to interact with the fluid stream 12 as it passes through the opening 26a and to sensory capture the fluid stream 12. In other words, the functional element 21 can be designed to detect properties of the fluid flow 12.

The above-described complementary functionality of two parts of the electronic circuit can be, for example, with respect to the gas sensor element on one side of the stack, for example the underside, and an electronic control on an opposite side of the stack. For example, it is possible that the production process for the gas sensor element, for example manufactured using MEMS technology, can not be integrated into the manufacturing process for the electronic circuit, for example manufactured in CMOS technology, on the front side at great expense, so that the Division of functionalities into complementary pairs enables the use of standard manufacturing processes. This can be done by using one of these standard processes to implement the drive function of the gas sensor on one wafer and the drive function for the electromechanical converters in another wafer, which are later brought together by wafer bonding to the MEMS converter, such as the MEMS converter. Transducer 180 to be connected. For example, the gas-sensing functional element 21 can enclose the opening 26a in order to provide the largest possible contact of a surface with the fluid flow 12. Alternatively or additionally, it is conceivable that the gas-sensing functional element at least partially protrudes into the opening, for example when an element for measuring a flow velocity or the like is arranged.

In other words, the layer 32b has an opening. An additional opening is located in the layer stack on the right side, for example. The fluidically interacting elements in layer 36, d. H. the deformable elements or the plate elements are, in this example, designed so as to form a micropump together with the cover layer and with the bottom layer 32a and 32b. For example, the ambient air could be drawn in via the opening 26a and expelled to the opening 26b. In the block 21 is, for example, a gas sensor, which is supplied by the proximity to the opening quasi-continuously with ambient air. This allows the sensor to react much faster to changes in ambient air than in the case of gas exchange based on fusion only.

19a shows a schematic view of a layer 27, which may be part of a layer stack of a MEMS converter according to exemplary embodiments. The layer 27 comprises a first main side 29a and a second main side 29b, wherein the left side of Fig. 19 is shown with the main side 29a visible and in the right side of Fig. 19 by rotation of the layer 27 about the axis 23 page 29b is visible. The side 29 a has an electronic structure 31 a, which has a first spacing grid 33 a. The second side 29b also has an electronic structure 31b which has a spacing grid 33b different therefrom. The electronic structures 31 a and 31 b may be electrically connected to each other within the adaptation layer 27, so that adaptation or conversion of the first spacing grid 33 a into the second spacing grid 33 b and vice versa is made possible by the adaptation layer 27. For example, the spacing grids 33a and 33b may be adapted to facilitate or facilitate contacting a respective side 29a or 29b with a particular type of electronic circuit. For example, one of the two pitches 33a or 33b may be configured to be compatible with a commonly used or standard screening of devices or boards, while the other pitch grid has a smaller pitch, for example, to provide a more compact design of circuit structures in the MEMS. Converter to be possible. Alternatively, distances in the pitch grid 33b may be larger than in the pitch grid 33a.

The layer 27 can be any layer in the layer stack, for example a layer that allows contacting with other components, for example the layers 32a and / or 32b in FIG. 17a. This means that the layer 27 can be a cover layer of the stack.

Alternatively, it is also possible for the layer 27 to be configured exclusively as an adaptation layer for adapting the spacing patterns, that is, the electronic circuit 17 does not have. Regardless, the layer 27 may be a cover layer of the stack, such as when the electronic circuit 17 is disposed only on one side of the stack. The layer 27 can be arranged as a cover layer of a stack, which is a use of the same interposer d. h., Translator allows. This means that it can also fulfill the function of an interposer. On this layer can then z. B. soldering or other suitable connection method for producing the electrical contacts, a further chip or circuit carrier with electronic and / or sensory func tionality are applied, which has the appropriate spacing grid. In embodiments it is provided that in this way, d. h., By the additionally contacted chips, the part or even the entire electronic functionality for the control / readout of the converter is realized or all additional sensory functionalities are provided.

Through MEMS technology, it is possible to place the gas sensor element not only in the vicinity of the opening 26a, but possibly also directly above the opening, ie, the gas sensor element may protrude into the opening. For this purpose, the sensory element can be suspended in the opening 26a. A pump with a previously described functionality may also utilize, for example, a portion of the available chip volume. In this way, another part, for example an area provided for a loudspeaker and / or a microphone, can be used for this purpose. Also, the chip volume or a portion thereof may be used as an ultrasonic transducer or for another function described herein. The use of the described technology is also possible as a microdosing unit with integrated sensors and signal processing. For example, a glucose sensor may be integrated as a MEMS element with a micropump, which is connected to an integrated, realized in the layer 36 reservoir. As soon as the glucose sensor indicates a critical blood sugar level, the pump can deliver the necessary amount of insulin from the reservoir. The same is conceivable for other medicaments and / or active substances such as analgesics, for example as a morphine or hydromorphone pump.

In other words, the novel approach is also based on the fact that the sound recording or the sound reproduction is performed by a MEMS chip, in which the fluidically active elements are not housed on the chip surface, but in the interior of the chip. As a result, the areas on the top and bottom of the chip remain completely or at least largely available for the monolithic integration of other sensors, actuators and electronic circuits. The illustrations here relate essentially to the use of this principle. However, the invention is not limited to this, but can generally be used for all MEMS loudspeakers and MEMS microphones in which the sound generation or processing takes place in the interior of a chip volume. FIG. 19b shows an advantageous use of the adaptation layer from FIG. 19a. As already mentioned, the adaptation layer can be embodied as a semiconductor layer, that is to say comprising semiconductor materials, such as silicon or gallium arsenide. On the first layer main side 29a, the adaptation layer 27 may have the first electronic structure 31a with the first spacing grid 33a. On the second, opposite layer main side 29b, the adaptation layer 27 may have the second electronic structure 31b with a second spacing grid 33b. The first and the second electronic structure 31 a and 31 b are electrically connected to each other, so that a contacting of an electrical circuit, such as the circuit 17 on one of the sides 29 a or 29 b, a conversion of the spacing grid 33 a or 33 b on the other spacing grid 33 b or 33a allows.

The adaptation layer 27 may be arranged in a MEMS layer stack, such as in a MEMS converter described herein. The MEMS layer stack may include a circuit layer 45 having an electronic circuit, such as the electronic circuit 17, having one of the pitch grids 33a or 33b. The layer 45 may be, for example, the layer 32b or another layer with an electronic circuit. The electronic circuit 17 can thus be electrically connected to the first or second electronic structure 31 a or 31 b, so that electrical circuit 17 can be contacted via the other layer main side 29 b and therefore with a different spacing grid, for which reason the layer 29 also acts as an interposer can be used. A layer stack connected to the adaptation layer 27 may be a layer stack described herein in the absence of the electronic controller 17. The layer stack can be connected to the layer stack by means of the adaptation layer 27 so as to carry out an evaluation and / or control of the deformable elements. If, for example, the MEMS converter 20 is considered, instead of the electronic circuit, the electronic structure for connection to the electronic circuit could also be arranged, which means that the layer 32b could be formed as an adaptation layer.

A MEMS layer stack according to embodiments described herein may form a MEMS transducer for interacting with the volume flow 12 of a fluid and include: the substrate 14 having a layer stack with a plurality of layers 32a-b, 34a-b, 36 forming a plurality of substrate planes and having a cavity 16 in the layer stack; an electromechanical transducer 18; 18a-f connected to the substrate 14 in the cavity (16) and an element 22 deformable in at least one plane of movement of the plurality of substrate planes; 22a-f; 30; 40; 150; 160, wherein a deformation of the deformable element 22; 22a-f; 30; 40; 150; 160 in the plane of motion and the volume flow 12 of the fluid are causally related;

The electronic circuit 17 is connected via the semiconductor layer with the electromechanical transducer 18; 18a-f connected. The electronic circuit 17 is configured to convert between a deformation of the deformable element 22; 22a-f; 30; 40; 150; 160 and provide an electrical signal.

A method of providing a semiconductor layer 27 comprises arranging a first electronic structure 31 a on a first layer main side 29 a of the semiconductor layer 27, such that the first electronic structure 31 a is a first spacing grid 33 a having. The method further comprises arranging a second electronic structure 31 b on a second, opposite layer main side 29 b of the semiconductor layer 27 so that it has a second spacing grid 33 b. The method comprises connecting the first and second electrical structures 31 a and 31 b with each other.

FIG. 20 shows a schematic block diagram of a MEMS system 200 having the EMS converter 80 connected to a controller 128 configured to process the signals to be provided to the MEMS converter 80 and / or that of the MEMS converter 80 MEMS converter to receive received signals. For example. For example, the electronic circuit may drive the electrodynamic transducer of the MEMS device 80 and / or receive electrical signals from the electrodynamic transducers of the MEMS device 80. Information as to how an appropriate control has to take place and / or an evaluation can be made in the control device 128. For example, if the MEMS converter 80 includes a plurality of electromechanical transducers 18, the controller 128 may be configured to provide information to the plurality of electromechanical transducers, such as a common electronic circuit and / or individual electronic circuits, such that a first and an adjacent second electromechanical transducer during a first time interval, at least locally move towards each other. The controller 128 may be configured to drive the at least one electronic circuit of a plurality of electromechanical transducers such that the first electromechanical transducer and a third electro-mechanical transducer disposed adjacent to the first electro-mechanical transducer interfere during a second interval. the move, the first electromechanical transducer can be arranged between the second and the third electromechanical transducer. For example, these may be the electromechanical transducers 8a-c, wherein the electromechanical transducer 18b may be the first electromechanical transducer. Alternatively or additionally, the controller 128 may be configured to receive and evaluate an electrical signal based on deformation of the deformable element from the electronic circuit. For example. For example, the controller 128 may be configured to determine a frequency or amplitude of deformation. This means that the system 200 can be operated as a sensor and / or actuator. For example, the system 200 may be operated as a MEMS loudspeaker, where the volumetric flow 12 may be an acoustic sound wave or a supersonic sound wave.

Alternatively, the system 200 may be implemented as a MEMS pump. A cavity of the substrate may have a first opening 26 and a second opening 26 in the substrate 14. The electromechanical transducer 18 may be configured to provide the volumetric flow 12 based on the fluid. The electromechanical transducer may be configured to move the fluid in a direction of the cavity based on actuation of the electromechanical transducer 18 through the first opening 26 or to move the fluid based on the actuation through the second opening in a direction away from the cavity to transport.

Alternatively, the system 200 may be operated as a MEMS microphone, wherein based on the deformation of the deformable member, an electrical signal may be obtainable at a terminal of the electro-mechanical transducer 80 or other connected electromechanical transducer. Based on the volume flow 12, the deformation of the deformable element can be effected.

Alternatively or additionally, MEMS transducers described herein may be embodied as a MEMS valve or MEMS dosing system. A MEMS dosing system can be used, for example, for implantable medication and / or insulin pumps.

Although the system 200 is described as connecting the controller 128 to the MEMS converter 80, another MEMS converter may be arranged, such as the MEMS converters 10, 20, 50, 100, 110, 170, 180 , 180 ', 230 and / or 240. Alternatively or additionally, a plurality of MEMS converters according to embodiments described above may be arranged. Alternatively or additionally, a stack of MEMS converters may be arranged MEMS transducers, such as the stack 90 or 140. Alternatively or additionally, at least two MEMS transducers may be arranged. At least one first MEMS converter and a second MEMS converter may have cavities or partial cavities and / or electromechanical transducers with mutually different resonance frequencies, for example a chamber with 500 Hz actuators, a further chamber or a further (partial) cavity 2 kHz actuators, etc.). The above-explained MEMS converters can be used in devices. An example of such a device 210 according to an exemplary embodiment is shown in FIG 21 a shown. The device 210 includes, for example, the MEMS transducer 10, but may alternatively or additionally include another MEMS transducer 20, 50, 100, 110, 170, 80, 180 ', 230, and / or 240 described herein. The MEMS Wandier is formed, for example as a MEMS speaker for generating an acoustic fluid flow 12 in the form of sound waves, the device 210 is designed as a mobile music playback device or headphones.

FIG. 21 b shows a schematic block diagram of a system 215 according to an exemplary embodiment, which, for example, may include the device 210. The MEMS Wandier 10 and / or another arranged MEMS Wandier can be designed as a speaker and be designed to reproduce an output signal 39 to reproduce an acoustic signal in the form of the Fiuidstroms 12. The output signal may be an analog or digital signal having acoustic information, such as voice information. The system 215 can be designed, for example, as a universal translator and / or as a navigation assistance system both for indoor applications (inside buildings) and outdoor applications (outside buildings). For this purpose, the system 215 further components, such as a microphone and / or a device for determining position and a computing unit, such as a CPU. The microphone may also be formed as a MEMS transducer described herein. The arithmetic unit may be configured to convert a speech content in a first language detected by the microphone into a second speech to provide the second speech output signal 39. Alternatively, the arithmetic unit may be configured to provide, based on a particular position, the output signal 39 having speech information regarding the detected position, which may then be reproduced by the MEMS transducer 10.

FIG. 22 shows a schematic representation of a health assistance system 220 according to one exemplary embodiment. The health assistance system 220 comprises a sensor device 35 for detecting a vital function of a body 37 and for outputting a sensor signal 39 based on the detected vital function. The health assistance system 220 comprises a processing device 41 for processing the sensor signal 39 and for providing an output signal based on the processing. The health assistance system 220 includes a headset, such as the device 200, including a MEMS wander according to any of the embodiments described herein. The MEMS Wandier is designed as a speaker and includes a wireless communication interface for receiving the output signal 43. The speaker 200 is configured to reproduce an acoustic signal based on the output signal 43. Benefits offers a realization of the speaker as headphones, especially as in-ear headphones. For example. The monitored vital function can be announced to the user, such as a pulse during exercise. It is also possible that a value derived from the vital function is output, such as the overshoot or undershoot of a threshold value or the like.

23 shows a schematic plan view of a MEMS converter 230 which has a multiplicity of electromechanical converters 18a to 18s, wherein the electromechanical converters 18a to 18f are laterally offset from one another laterally in a first cavity 16a and the electromechanical converters 18g to 18i are laterally juxtaposed offset from each other in a second cavity 16b are arranged. The cavities 16a and 16b may have an opening in a bottom and / or top surface of the substrate 14, not shown. The MEMS converter 230 can be used as a loudspeaker and / or microphone, which applies to individual electromechanical transducers 18a to 18s as well as to the electromechanical transducers 18a to 18f or 18g to 18i of a respective cavity 16a and 16b. The speakers and / or microphones can also be designed so that it is optimized for the delivery or recording of sound waves via vibrations. For example, it may be placed with the human body, ideally close to a bone, to transmit or record information by means of structure-borne noise. In this case, a preferred variant is that in which all the actuators move in the same direction, that is, independent of an approach that a chamber has two movable walls. The electromechanical transducers 18a to 18i comprise cantilevered beam elements. The MEMS converter 230 includes the electronic circuit 1 7, not shown.

In other words, the left chamber, cavity 16a, contains laterally or vertically movable bender actuators, which preferably vibrate in phase, vibrating the chip to transmit sound. The right chamber, cavity 16b, contains three lateral or vertical bending actuators, which also preferably oscillate in phase, but which by their dimensioning (thickness, length or width) represent a different frequency range than the left chamber. FIG. 24 is a schematic plan view of a MEMS converter 240 having a plurality of electromechanical transducers 18a to 18i, the electromechanical transducers 18a to 18i Transducers 18a to 18f laterally offset from each other are arranged side by side and each adjacent cavities 16a to 16k or part cavities spaced from each other. The electromechanical transducers 18a to 8i comprise cantilevered beam elements. The EMS converter 240 includes the electronic circuit 17, not shown.

Although the exemplary embodiments of FIGS. 23 and 24 are illustrated such that the MEMS converter 230 has exclusively bar elements clamped on one side and the MEMS _: converter 240 has bar elements clamped on both sides only, the embodiments can also be combined with one another as desired, so that each cavity 16a or 16b independently of each other similar electromechanical transducers or within a cavity various electromechanical transducers can be arranged. In other words, Fig. 24 shows a same principle as in Fig. 23, but this time used both sides clamped bending actuators.

Further exemplary embodiments relate to a method for producing a MEMS converter. The method includes providing a substrate comprising a layer stack having a plurality of layers forming a plurality of substrate planes and having a cavity in the layer stack. The method comprises generating an electromechanical transducer in the substrate so that it is connected to the substrate in the cavity and has a deformable in at least one plane of movement of the plurality of substrate planes element, wherein a deformation of the deformable element in the plane of motion and the Volume flow of the fluid causally related. The method includes placing an electronic circuit in a layer of the layer stack so that the electronic circuit is connected to the electromechanical transducer and configured to provide a conversion between deformation of the deformable element and an electrical signal.

Although embodiments described above relate to the volumetric flow being producible by moving two electromechanical transducers toward each other, the volumetric flow can also be obtained based or in causal interaction with movement of an electromechanical transducer relative to a rigid structure such as the substrate. That means a volume of one Partial cavity or a Teilkavitätsabschnitts may be influenced by a single electromechanical transducer.

Previously described embodiments having a deformable member configured to perform a multiple curvature and / or connected to a plate member may be useful as compared to the configuration described in connection with FIG in order to generate a significantly higher volume flow or to react more sensitively to a volume flow.

Embodiments make it possible to make the frequency-dependent progression of the sound pressure flexibly adjustable, in order in particular to enable the frequently desired case of a flat frequency response as possible. In order to design a frequency-dependent sound pressure curve with as few chambers of the MEMS converter as flat as possible, it is advantageous if the quality of the oscillating bending beam is low, d. H. the bending beams have a broad resonance curve. For this purpose, the clamping of the beams can be carried out so that by means of a damping material, the beam vibration is additionally attenuated. The clamping of the beam is preferably made of a non-crystalline material. These include silica, polymers, such as. B. SU8 or other resists. An attenuation of the bar oscillation can also be achieved electrically. For example, during the free beam oscillation in the case of an electrostatic or piezoelectric actuator, due to the change in the capacitance, a periodically alternating current flows when the voltage is present. By suitably provided electrical resistances creates a power loss, which leads to the damping of the vibration. Also, a complete electrical resonant circuit (i.e., an integrated or external coil is additionally provided) is possible. Damping can also be achieved by implementing additional structures on the bending beams which provide a significant flow resistance for the fluid as it flows in and out of the chamber.

Especially for the representation of low resonance frequencies - for the generation or detection of low frequencies - it may be advantageous to increase the mass of the bending beam. In order not to significantly increase the rigidity, additional structures are preferably applied in the region of the greatest vibration amplitudes. In the case of a cantilever beam, the optimal location or area is the largest Vibration amplitudes the end of the bending beam. In the case of a two-sided clamped beam, this is the middle of the beam.

In other words, one finding of the present invention is that compression or expansion of chambers, i. H. Partial cavities or Teilkavitätsabschnit- th which can be formed in a silicon chip, a volume flow is generated or becomes detectable. Each chamber may be provided with an inlet or outlet through which a fluid, such as air, may flow in and out. The chambers may be closed by a fixed lid along a direction perpendicular to the lateral direction of movement (eg, top and bottom). At least one of the lateral walls of each chamber is designed to be movable or deformable and can be displaced by an actuator in such a way that the volume of this chamber is reduced or increased.

Previously described embodiments of MEMS Wandiern may have electrical connections see, bond pads or the like, which are not shown in the figures for clarity.

Embodiments described above relate to reusable loudspeakers or N-way loudspeakers which can be obtained based on different resonance frequencies of at least two cavities or partial cavities. The electromechanical transducers and the cavities or partial cavities can be matched to one another such that a sound pressure level (SPL) is at least partially a function of the resonant frequency, ie several actuator chambers can have different frequency characteristics (SPL = f (frequency)). This means that values of sound pressure levels, which are obtained based on the deformation of the deformable elements and based on the partial cavities, have a relationship with a frequency of the volume flow flowing out of or into the respective partial cavity. The relationship may be represented as a function, where the function may, for example, be linear, such as SPL = x ^* frequency + b, where x and b are variables. Alternatively, the function may be nonlinear, such as quadratic, exponential, or based on a root function. The functional relationship can be easily transferred to different partial cavities or cavities arranged in different MEMS transducers. Thus, the frequency of the volumetric flow can describe a frequency-dependent course of a pressure in the fluid. The silicon chips of the MEMS andler can be designed and so out of the disk composite, which is obtained during a wafer-level manufacturing, be dissolved out that they have an adapted form for each application. So the chip z. B. for use as speakers in hearing aids or in-ear headphones, for example, round or, which is more suitable for the consumption of silicon surface on the disc, hexagonal design.

The technical design of the monolithic integration of microelectronic components or microsystems on the surface and lower surface of a MEMS loudspeaker, which uses the chip volume for sound generation, can be supplemented by several aspects. The microelectronic components, such as the MEMS structures, can be integrated into one or more layers. The electronic control or evaluation circuit, ie the electronic circuit 17, may comprise a digital-to-analog converter and / or a PWM generator. A signal conditioning can be done for example by digital signal processing, which may be part of the electronic circuit 17. The electronic circuit 17 may further comprise clocks and / or oscillators, may comprise a high-voltage generation, ie a DC / DC converter, a charge pump or a boost converter, a decoder, such as for digital audio signals such as the "sound wire" standard or a Furthermore, the electronic circuit may comprise an amplifier or a current bank The electronic circuit 17 may comprise a processor, such as a CPU, which may be used for example for text-to-speech or speech-to-text algorithms. Furthermore, the electronic circuit 17 may comprise a semiconductor memory such as a RAM or a flash memory The MEMS converters may comprise MEMS sensors such as acceleration sensors, temperature sensors, rotation rate sensors, position sensors or magnetic field sensors which are part of the electronic circuit 7 or more Circuit components can be controlled or read R moisture sensors or gas sensors are provided. Alternatively or additionally, it is possible to provide radio interfaces and / or wireless interfaces for near field communication, such as a Bluetooth interface. It is also possible that a mobile radio interface, for example for LTE and / or eSIM (embedded SIM), is provided for a machine-machine interface such as iBeacon or physical web. Alternatively or additionally, a receiver for global navigation satellite systems such as GBS can be integrated. The MEMS converters may be embodied as MEMS microphones and / or MEMS loudspeakers or the like. The MEMS converters enable a system function, ie a combination with other functions or applications. These include, for example, MP3 players, signage technology, streaming, headset, walkie talkie and the like. Also, an application in hearing aids is possible. Health assistance systems such as fitness trackers that allow for recording, comparison, optimization and / or announcement of vital signs, including step count, body temperature, respiratory rate, and / or energy consumption are also conceivable. Systems may also relate to navigation assistance systems, for example, in public space and / or within buildings via speech-to-text and / or text-to-speech technologies or enable algorithms support. This may, for example, refer to a specific group of persons, such as the blind, and / or to certain buildings, such as public buildings, military buildings, police buildings or fire-brigade buildings. In control systems, embodiments described herein may be used, for example, to control communication and devices by gestures and speech. Here, for example, a human-machine interface can be provided via speech-to-text and / or text-to-speech technologies and / or algorithms. Also, applications in the university translation are conceivable, for example, for a simultaneous translation in the language area. Virtual reality applications are also implementable, such as a purely acoustic virtual reality, such as for blind people, a supporting visual virtual reality, also referred to as augmented reality, an audible internet, audible social networks, etc. Alternatively or additionally For example, security-relevant logins, for example for an audible Internet and a human-machine communication, can be implemented, and a recognition of safety-critical acoustic events, for example a call for help, can also be implemented Also for MEMS microphones that record acoustic signals, although some aspects have been described in connection with a device, it should be understood that these aspects are also a description of the corresponding method, so that e in block or a component of a device is also to be understood as a corresponding method step or as a feature of a method step. Similarly, aspects described in connection with or as a method step also represent a description of a corresponding block or detail or feature of a corresponding device. The embodiments described above are merely illustrative of the principles of the present invention. It will be understood that modifications and variations of the arrangements and details described herein will be apparent to others of ordinary skill in the art. Therefore, it is intended that the invention be limited only by the scope of the appended claims and not by the specific details presented in the description and explanation of the embodiments herein.

literature

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[2] Roberts, Robert C. et al.: Electrostatically Driven Touch-Mode Poly-SiC Microspeaker, Sensors, IEEE 2007 (2007), p. 284-287.

[3] Kim, H. et al .: Bi-Directional Electrostatic Microspeaker with Two Large-Deflection Flexible Membranes Actuated by Single / Dual Electrodes, Sensors, IEEE 2005

(2005), p. 89-92.

[4] Rehder, J .; Rombach, P .; Hansen, O .: Magnetic flux generator for balanced mem- brane loudspeaker. In: Sensors and Actuators A: Physical 97 (2002), No. 8, p. 61-67.

[5] Neri, F .; Di Fazio, F .; Crescenzi, R .; Balucani, M .: A novel micromachined loudspeaker topology. In: 61 st Conf. on Electronic Components and Technology, ECTC, IEEE 201 1 (201 1), p. 1221-1227. [6] Neumann, J.J., Gabriel, K.J .: CMOS-MEMS Acoustic Devices, in: Advanced Micro and Nanosystems, Vol. 2. CMOS-MEMS. Edited by H. Baltes et al., Wiley-VCH Verlag, Weinheim (2005).

[7] Lerch R .; Sessler, G .; Wolf, D .: Technical Acoustics, Springer Verlag (2009).

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Claims

claims

A MEMS Wandier for interacting with a volume flow (12) of a fluid comprising: a substrate (14) having a layer stack with a plurality of layers (32a-b, 34a-b, 36) forming a plurality of substrate planes, and having a cavity (16) in the layer stack; an electromechanical transducer (18; 8a-f) connected to the substrate (14) in the cavity (16) and a deformable in at least one plane of movement of the plurality of substrate planes element (22; 22a-f; 30; 40; 150; 160), wherein deformation of the deformable element (22; 22a-f; 30; 40; 150; 160) in the plane of motion and the volume flow (12) of the fluid are causally related; an electronic circuit (17; 17a-b) disposed in a layer (32a-b) of the layer stack, the electronic circuit (17; 17a-b) being connected to the electromechanical transducer (18; 18a-f), and configured to provide a conversion between deformation of the deformable member (22; 22a-f; 30; 40: 150; 160) and an electrical signal.

A MEMS converter according to claim 1, wherein the electronic circuit (17; 17a-b) is adapted to provide an electrical drive signal (In) into a deflection of the deformable element (22; 22a-f; 30; 40; 150; 160). or to convert a deformation of the deformable element (22; 22a-f; 30; 40; 150; 160) into an electrical output signal (Out ₂ ).

A MEMS converter according to claim 2, wherein the electronic circuit (17; 17a-b) comprises at least one of a digital Anaiog Wandier for converting a digital version of the drive signal (ln-ι) in an analog version of the drive signal (Out, ), an analog-to-digital converter for converting an analog version of the electrical output signal (In,) into a digital version of the electronic output signal (Out), a signal decoder, a processor, a semiconductor memory, a wireless communication interface for near-field communication and a Mobile interface includes. A MEMS converter according to claim 2 or 3, wherein said electronic circuit (17; 17a-b) is adapted to rotate said electrical drive signal (In) into a deflection of said deformable element (22; 22a-f; 30; 40; 150) 160) and includes a switching amplifier configured to provide a digital pulse width modulated drive signal to the deformable element (22; 22a-f; 30; 40; 150; 160).

A MEMS transducer according to any one of claims 2 to 4, wherein the deformable member (22; 22a-f; 30; 40; 150; 160) comprises a first deformable member (22; 22a-f; 30; 40; 150; 160). wherein the MEMS converter comprises at least one second deformable element (22; 22a-f; 30; 40; 50; 160), wherein the electronic circuit (17; 17a-b) is designed to generate the electrical drive signal (In). in a deflection of the first and second deformable members (22; 22a-f; 30; 40; 150; 160), or to deform the first and second deformable members (22; 22a-f; 30; 40; 150, 160) into the electrical output signal (Out ₂ ).

A MEMS transducer according to any one of the preceding claims, wherein the deformable member (22; 22a-f; 30; 40; 150; 160) is actively formed and configured to interact with the flow stream (12); or a plate member (62; 62a-c) connected to the deformable member (22; 22a-f; 30; 40; 150; 160) is formed to interact with the volumetric flow (12)

A MEMS converter according to any one of the preceding claims, wherein the layer (32a-b) in which the electronic circuit (17; 17a-b) is disposed is arranged along a direction perpendicular to the plane of movement.

A MEMS converter according to any one of the preceding claims, wherein the layer (32a-b) in which the electronic circuit (17; 17a-b) is disposed is electrically connected to an outside of the MEMS converter or the outside of the MEMS converter is, and is contactable with a line arrangement.

A MEMS converter according to any one of the preceding claims, wherein the layer (32a-b) in which the electronic circuit (17; 17a-b) is disposed is a first lid layer, the electronic circuit (17; 17a-b) being a first one electronic circuit (17a), and wherein a second electronic circuit (17b) is disposed in a second cover layer of the substrate (14). A MEMS transducer according to claim 9, wherein said deformable member (22; 22a-f; 30; 40; 150; 160) is at least temporarily disposed between said first and second electronic circuits (17a, 17b) during deformation.

1 1. A MEMS converter according to claim 9 or 10, wherein the second electronic circuit (17b) is connected to the electromechanical transducer (18; 18a-f) or to the first electronic circuit (17a) and adapted to be coupled to the first electronic Circuit (17a) complementary function in connection with the deformable element 22; 22a-f; 30; 40; 150; 160).

12. MEMS converter according to one of the preceding claims, wherein the layer stack has an adaptation layer (27) on a first layer main side (29 a) first electronic structure (31 a) having a first spacing grid (33 a) and at a second , the opposite main layer side (29b) second electronic structure (31 b) having a second pitch grid (33b), wherein the first electronic structure and the second electronic structure in the adaptation layer are connected to each other.

13. A MEMS converter according to claim 12, wherein the adaptation layer (27) is a lid layer of the stack in which the electronic circuit (17; 17a-b) is at least partially disposed, or a lid layer of the stack which is electrically exclusive of Adaptation layer is formed.

14. MEMS converter according to one of the preceding claims, in which the layer (32a-b) in which the electronic circuit (1 7; 7a-b) is arranged comprises a functional element (21) connected to the electronic circuit (17 17a-b), wherein the electronic circuit (17; 17a-b) is adapted to drive or evaluate the functional element (21).

A MEMS converter according to any one of the preceding claims, wherein the layer (32a-b) in which the electronic circuit (17; 17a-b) is disposed is a first lid layer, the electronic circuit (17; 17a-b). a first electronic circuit (17a) is, and in which a second electronic circuit (17b) and a functional element (21) in a second cover layer of the substrate (14) is arranged, wherein the second electronic circuit (17b) with the functional element (21 ), and is designed to control or evaluate the functional element (21). 16. A MEMS converter according to claim 14 or 15, wherein the functional element (21) comprises at least one of a sensor, an actuator, a wireless communication interface, a light source, a memory module, a processor and a navigation receiver.

17. The MEMS converter according to claim 16, wherein the functional element (21) comprises at least one of a MEMS sensor and a MEMS actuator.

18. The MEMS converter according to claim 1, wherein the electronic circuit is arranged in a cover layer of the substrate, and further wherein a gas sensor functional element is arranged in the cover layer the cover layer has an opening (26a) which is designed to allow the fluid flow (12) to pass, wherein the gas-sensory functional element is designed to interact with the fluid flow (12) in a sensor-like manner.

19. MEMS converter according to claim 18, in which the opening is enclosed by the gas-sensing functional element (21) in the cover layer. 20. MEMS converter according to claim 18, in which the gas-sensing functional element (21) projects at least partially into the opening (26a).

21. A MEMS converter according to any one of the preceding claims, wherein the layer (32a-b) in which the electronic circuit (17; 17a-b) is disposed is a first substrate layer, and wherein the electronic circuit (17; 17a-b ) is at least partially disposed in an adjacent second substrate layer.

22. A MEMS converter according to one of the preceding claims, wherein the electronic circuit (17; 17a-b) is arranged along a direction perpendicular to the plane of movement, and a location of the electronic circuit (17; 17a-b), when projected into the plane of motion corresponds to a location where the deformable element (22; 22a-f; 30; 40; 150; 160) is at least temporarily during deformation. 23. MEMS converter according to one of the preceding claims, in which the electromechanical converter (18; 18a-f) is designed to operate in response to an electrical control (Out, Outi) of the electronic circuit (17; 1 7a-b). causally cause movement of the fluid in the cavity (16) and / or to be appealing to causally provide an electrical signal (Out ₂ ) with the electronic circuit (17; 17a-b) to the movement of the fluid in the cavity (16).

A ME S transducer according to any one of the preceding claims, comprising a plurality of electromechanical transducers (18; 18a-f), said first and second deformable members (22; 22a-f; 30; 40; 150; 160) having a beam structure (30) configured to warp along an axial direction of the beam structure (30); wherein between the beam structures (30) of the first electromechanical transducer (18b, 18d) and the second electromechanical transducer (18c, 18e), a first Teilkavität (42a, 42b) is disposed adjacent to an opening (26) of the substrate (14)

A MEMS transducer according to any one of the preceding claims, comprising a plurality of electromechanical transducers (18; 18a-f) connected to the substrate (14) and a respective deformable element (22; 22a) along the lateral direction of movement (24) -f; 30; 40; 150; 160); wherein a first subcavity (42a, 42b) is arranged between a first electromechanical transducer (18b, 18d) and a second electro-mechanical transducer (18c, 18e) and between the second electro-mechanical transducer (18b, 18d) and a third electro-mechanical transducer (18a, 8c) a second partial cavity (38a, 38b) is arranged.

The MEMS transducer of claim 25, wherein the first and second electromechanical transducers (18b, 18d) are configured to vary a volume of the first subcavity at a first frequency, the first (18b, 18d) and the third electromechanical transducers (18a, 18c) are adapted to vary a volume of the second subcavity at a second frequency. 27. The MEMS transducer according to claim 25, wherein the substrate has a plurality of openings connected to a plurality of partial cavities of the cavity, wherein a volume of each partial cavity is of a deflection state at least one deformable along the lateral direction of movement element is influenced, wherein two adjacent sub-volumes of partial cavities are complementarily increased or reduced during the first or second time intervals. An EMS converter according to any one of claims 25 to 27, wherein the deformable elements (22; 22a-f; 30; 40; 150; 160) of the first electromechanical transducer (18b, 18d) of the second electromechanical transducer (18c, 18e) and the third electromechanical transducer (18a, 18c) comprise a beam actuator (30) having first and second ends, respectively, the beam actuator (30) of the first electromechanical transducer (18b, 18d) at the first end and the second end is connected to the substrate (14), wherein the beam actuator of the second electro-mechanical transducer (18c, 18e) or the third electro-mechanical transducer (18a, 18c) is connected in a central region of the beam actuator with the substrate (14).

A MEMS transducer according to any one of claims 25 to 28, wherein the substrate (14) has a plurality of apertures (26) connected to a plurality of sub-cavities (42a-b, 38a-c) of the cavity (16). wherein a volume of each sub-cavity (42a-b, 38a-c) is influenced by a deflection state of at least one deformable element (22; 22a-f; 30; 40; 150; 160), wherein values of sound pressure levels , which are obtained based on the deformation of the deformable elements (22; 22a-f; 30; 40; 150; 160) and based on the partial cavities (42a-b, 38a-c), a relationship with a frequency of the volume flow (12 ), which flows out of or into the respective partial cavity (42a-b, 38a-c), which can be represented as a function; wherein the frequency of the volume flow (12) describes a frequency-dependent course of a pressure in the fluid.

A MEMS transducer according to any one of the preceding claims, wherein the electromechanical transducer (18; 18a-f) comprises a plurality of deformable elements (22; i) at least indirectly connected in the axial direction (y) of the electromechanical transducer (18; 22a-f; 30; 40; 150; 160). which are designed to each have a volume of a first and a second partial cavity section (96a,

96b). The MEMS transducer of claim 30, wherein the electromechanical transducer (18; 18a-f) is configured to causally move the fluid in the first (96a) and second subcavity portions (96b) in response to an electrical drive (129a) the deformable elements (22; 22a-f; 30; 40; 150; 160) are adapted to change the volumes of the first (96a) and second Teilkavitäts- section (96b) with a different frequency from each other.

32. MEMS transducer according to one of the preceding claims, wherein the deformable element (22; 22a-f; 30; 40; 150; 160) is contact-free relative to a layer (32a-b) defining the cavity (16) parallel to the plane of movement. or wherein a low-friction layer is arranged between the deformable element (22; 22a-f; 30; 40; 150; 160) and the layer (32a-b) defining the cavity (16) parallel to the plane of movement is.

33. A MEMS converter according to one of the preceding claims, wherein the deformable element (22; 22a-f; 30; 40; 150; 160) is formed as a bimorph having an actuation direction (59, 59) along which the deformable element (22; 22a-f; 30; 40; 150; 160) is deflectable by applying an electrical voltage.

34. The MEMS transducer of claim 33, wherein the deformable element (22; 22a-f;

30; 40; 150; 160) comprises a first (30a), a second (30b) and a third beam segment (30c) arranged in this order along the axial direction (y) and each having opposite directions of actuation (59a-c).

35. A MEMS converter according to claim 34, wherein the electromechanical transducer (18;

18a-f) comprises first and second deformable members (22; 22a-f; 30; 40; 150; 160), wherein an outer Baikensegment (30a, 30c) of the first deformable member (22; 22a-f; 30; 40; 150; 160) and an outer beam segment (30a, 30c) of the second deformable member (22; 22a-f; 30; 40; 150; 160) are at least indirectly interconnected.

A MEMS transducer according to any one of the preceding claims, wherein the substrate (14) comprises an anchor member (84); wherein the deformable member (22; 22a-f; 30; 40; 150; 160) in a central region (30b) of an axial extension direction (y) of the deformable member (22; 22a-f; 30; 40; 150; 160) the Ankereiement (84) is connected; or wherein the deformable element (22; 22a-f; 30; 40; 150; 160) on an outer beam segment (30a, 30c) is connected via the anchor element (84) to a further deformable element.

A MEMS transducer according to any one of the preceding claims, wherein the deformable element (22; 22a-f; 30; 40; 150; 160) has a beam structure, the beam structure being fixedly clamped at first and second ends.

The MEMS transducer according to one of the preceding claims, wherein the cavity (16) has an opening (26) in the substrate (14) which is arranged perpendicular to the lateral movement direction (24), so that the volume flow (12) based on the Deformation of the deformable element (22; 22a-f; 30; 40; 150; 160) perpendicular to the lateral direction of movement (24) from the cavity (16) or into the cavity (16) flows.

A MEMS transducer according to any one of the preceding claims, wherein the deformable element is disposed adjacent the aperture (26).

A MEMS converter according to any one of the preceding claims, embodied as one of a MEMS pump, a MEMS speaker, a MEMS microphone, a MEMS valve, a MEMS dosing system.

41. Device having a MEMS converter according to one of the preceding claims, in which the MEMS converter is designed as a MEMS loudspeaker, wherein the device is designed as a mobile music playback device or as headphones.

42. A MEMS transducer system according to any one of claims 1 to 38, wherein the MEMS transducer is implemented as a loudspeaker and is adapted to reproduce an audible signal based on an output signal.

43. System according to claim 42, which is designed as a universal translator or as a navigation assistance system.

44. semiconductor layer having on a first layer main side (29 a) a first electronic structure (31 a) with the first spacing grid (33 a) and on a second, opposite layer main side (29 b) a second electronic Structure (31 b) having a second pitch grid (33 b), wherein the first and the second electronic structure (31 a, 31 b) are electrically connected to each other.

A MEMS layer stack comprising a semiconductor layer according to claim 44 and comprising a circuit layer comprising an electronic circuit (17) comprising a first pitch grid (33a); wherein the electronic circuit (17) is connected to the first electronic structure so that electrical circuit (17) is contactable via the second layer main side (29b).

The MEMS layer stack of claim 45 forming a MEMS transducer for interacting with a fluid flow (12) comprising: a substrate (14) comprising a layer stack having a plurality of layers (32a-b, 34a); b, 36) forming a plurality of substrate planes and having a cavity (16) in the layer stack; an electromechanical transducer (18; 18a-f) connected to the substrate (14) in the cavity (16) and an element (22; 22a-f; 30; 40; 40) deformable in at least one plane of movement of the plurality of substrate planes; 150; 160), wherein deformation of the deformable element (22; 22a-f; 30; 40; 150; 160) in the plane of motion and the volume flow (12) of the fluid are causally related; the electronic circuit (17) being connected to the electromechanical transducer (18; 18a-f) via the semiconductor layer; wherein the electronic circuit (17; 7a-b) is adapted to provide a conversion between deformation of the deformable member (22; 22a-f; 30; 40; 150; 160) and an electrical signal.

A health assistance system (220) comprising: sensor means (35) for detecting a vital function of a body (37) and outputting a sensor signal (39) based on the detected vital function; processing means (41) for processing the sensor signal (39) and providing an output signal (43) based on the processing; and a headset (200) comprising a MEMS converter according to any one of claims 1 to 38, wherein the MEMS converter is implemented as a loudspeaker and which comprises and is designed to receive a wireless communication interface for receiving the output signal (43) to play the acoustic signal.

Health assistance system according to claim 47, wherein the headset is formed as in-ear headphones.

Method for providing a MEMS converter for interacting with a volume flow (12) of a fluid, comprising the following steps:

Providing a substrate (14) comprising a layer stack having a plurality of layers (32a-b, 34a-b, 36) forming a plurality of substrate planes and having a cavity (16) in the layer stack;

Producing an electromechanical transducer (18; 18a-f) in the substrate (14) so that it is connected to the substrate (14) in the cavity (16) and a deformable element in at least one movement plane of the plurality of substrate planes (FIG. 22; 22a-f; 30; 40; 150; 160), wherein deformation of the deformable element (22; 22a-f; 30; 40; 150; 160) in the plane of motion and the volume flow (12) of the fluid are causally related ;

Arranging an electronic circuit (17; 17a-b) in a layer (32a-b) of the layer stack so that the electronic circuit (17; 17a-b) is connected to the electromechanical transducer (18; 18a-f) and formed to provide a conversion between deformation of the deformable member (22; 22a-f; 30; 40; 150; 160) and an electrical signal.

Method for providing a semiconductor layer, comprising the following steps:

Arranging a first electronic structure (31 a) on a first layer main side (29 a), such that the first electronic structure has a first spacing grid (33 a); Arranging a second electronic structure (31b) on a second opposite layer main side (29b) so that it has a second spacing grid (33b); and

Connecting the first and second electrical structure (31 a, 31 b) with each other.